We are going to present for the first time Negative Ion Drift (NID) operation in He:CF4:SF6 at nearly atmospheric pressure within a Time Projection Chamber (TPC) with optical readout via PMTs and scientific CMOS camera (sCMOS). These results have been obtained in the context of the CYGNO/INITIUM project, for the development of high precision 3D TPC for directional direct Dark Matter searches....
Modeling accurately biological damage induced by ionizing radiation at the scale of the DNA molecule remains a major challenge of today’s radiobiology research (1). In order to provide the community with an easily accessible mechanistic simulation platform, the general purpose and open source “Geant4” Monte Carlo simulation toolkit (2) is being extended in the framework of the “Geant4-DNA”...
Most forensic studies deal with the identification and characterization of a sample, which is the evidence of some crime activity, comparison of samples coming from different sources, and interpretation of the results obtained in the context of the events. X-ray instrumentation has been commonly used in forensic science and also in some related fields such as Cultural Heritage objects...
Since the dawn of the chirped-pulse era [1], rotational spectroscopy emerged as an outstanding tool for structure-solving, enabling novel exploratory approaches with unprecedented tracing capabilities [2]. The enhanced sensitivity and broadband capabilities of chirped-pulse microwave spectroscopy unlocked investigations into increasingly intricate molecular species [3], including notable...
The molecular complexity in the interstellar medium increases in cold molecular clouds, at approximately 10 K. It is then important to establish the reactivation rate constants in chemical networks taking place in gas phase, as alternative to those taking place on cosmic ices. At 10 K, quantum effects, such as tunneling and zero point energies are very important. Complex forming reactions are...
Graphene quantum dots (GQD) are nanoparticles consisting of a single or several layers of graphene sheets whose thickness does not exceed 100 nanometers. For their ease of preparation, biocompatibility and tunable absorption and emission properties, they have become extremely popular in optoelectronics, as nanocarriers for cancer therapy drugs and in bioimaging techniques.[1]
In this work,...
Silicates are ubiquitously found as small dust grains in the interstellar medium, where they are processed due to high-energy processes, such as UV radiation absorption. These abundant nanosilicates are likely to play an important role in astrochemistry. In this work, we form small magnesium silicate clusters via laser vaporization of a binary Mg2Si target in the presence of diluted molecular...
Hydrogen-bonded networks sustain a broad range of structural and charge transfer processes in supramolecular materials. The modelling of the proton dynamics in these systems is challenging and demands insights into prototypical benchmark complexes. Intramolecular H-bonding in 3-hydroxyglutaric acid (M) provides an intriguing case study of entangled proton dynamics. We combine infrared action...
We use a multiconfiguration Dirac-Fock code [1,2] to calculate electronic excitation cross sections and radiative decay transition probabilities for a large number of atomic levels in Pm-like bismuth. By numerically solving a set of equilibrium equations we were able to obtain the level populations of the $4f^{14}5s$, $4f^{13} 5s5f$, $4f^{13} 5s5d$, $4f^{13} 5s5p$, and $4f^{13} 5s^2$...
The production of electricity from nuclear fusion has been a long-term challenge addressed by many research teams around the world. Recent records from inertial fusion and in magnetic confinement fusion experiments open great perspectives for a successful outcome in this quest. ITER construction is being accompanied by a vibrant fusion research program in many countries but, in particular in...
The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen (µp) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with $2×10^{−4}$ relative accuracy. In the proposed experiment, the µp atom undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine...
In today's world, the great pollution puzzle is undoubtedly the greatest challenge facing the world's population. Dioxins and dibenzofurans are persistent organic pollutants (POPs); the more toxic forms correspond to their tetrachlorinated derivatives, 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF). The reduction of their emissions, the elimination of...
Microfluidics devices with internal gas flows are nowadays subject of a rapid development. These devices often operate in rarefied gas flow regimes, since the ratio of the molecular mean free path over the channel dimensions becomes non-negligible. In those rarefied flows, effects like temperature-jumps near the wall are expected to occur. However, there is a lack of experimental techniques...
Neutrons play a dominant role in the stellar nucleosynthesis of heavy elements. We review a scheme for the experimental determinations of neutron-induced reaction cross sections using a high-intensity neutron source based on the 18O(p,n)18F reaction with an 18O-water target at SARAF’s upcoming Phase II. The quasi-Maxwellian neutron spectrum with effective thermal energy kT ≈ 5 keV,...
Two-dimensional materials are comprised of single- or few-layers of atoms arranged in a crystalline lattice structure. These materials exhibit unique properties due to their ultrathinness and the ability to adjust the number of layers. The research field surrounding these materials has gained significant interest since the discovery of graphene and its derivatives [1]. Recently, other 2D...
We present recent results on the photophysics and optical properties of
nanographenes. The first part of the talk focuses on the photophysics of cove-edge hexa-peri-hexabenzo-bis-peri-octacenes. The remarkable light emission properties and lack of excited state absorption upon solvation give rise to net stimulated emission and amplified spontaneous emission, largely enabled by the cove-edge...
Practical density functional theory (DFT) owes its success to the groundbreaking work of Kohn and Sham that introduced the exact calculation of the non-interacting kinetic energy of the electrons using an auxiliary mean-field system. However, the full power of DFT will not be unleashed until the exact relationship between the electron density and the non-interacting kinetic energy is found....
Gas Proportional Scintillation Counters (GPSC) are gas-filled detectors in which the charge signal produced by radiation interaction is amplified by secondary scintillation promoted by electron impact (electroluminescence) taking place in the gas. Primary electrons produced by the interacting radiation are driven towards a scintillation region, where the applied electric field is high enough...
The interest in CuInS2 (CIS) quantum dots (QDs) has increased significantly in the past few years due to broad range of their potential applications, such as photodynamic therapy or solar cells [1]. This owes to extraordinary optoelectronic properties of this material, such as broad photoluminescence with a large Stokes shift and long charge carrier lifetimes. To elucidate the...
Azobenzene derivatives are becoming increasingly popular in pharmacology due to their improved selectivity based on trans-cis isomerization upon light irradiation. In the context of ion channels, one of the conformations may block ion conduction, while the other allows it. We studied an azobenzene derivative, DAD, designed with the aim of avoiding excitation wavelengths in the UV region of the...
Electroluminescence (EL) is the phenomenon of light emission, by a material, following electron impact in the presence of an external electric field. Gas Proportional Scintillation Counters (GPSC) use this effect in noble gases as an amplification process of the ionization signal induced by radiation interaction in the gas. Several geometries have been proposed and developed for this type of...
Primary scintillation in Xe for electrons and alpha-particles Content Gaseous xenon (GXe) is playing an increasingly significant role in important areas of neutrino physics such as double beta decay and double electron capture experiments and is a potential alternative to MeV-region γ-ray imaging. The precise knowledge of the xenon response to radiation interactions in both scintillation and...
Wave-Length Shifting (WLS) fibers are optical fibers specially designed to shift the wavelength of incident ultraviolet or blue light to longer wavelengths, namely green light. The usage of WLS fibers for xenon scintillation readout offers several advantages, including enhanced light yield due to efficient conversion of UV/blue scintillation photons to visible light, reduced sensitivity to...
Global concern about the high environmental impact of hydrofluorocarbons (HFCs) led the Kyoto Protocol to list these compounds as potent greenhouse gases. For that reason, hydrofluoroethers (HFEs) were proposed for substitution of HFCs in several applications, such as refrigerants, because of their relatively low global warming potential (GWP). Therefore, it is important to evaluate the impact...
In the last years, several C-bearing and (C,N)-bearing chains of molecular anions have been detected in the interestellar medium (ISM). Since experimental treatments are still challenging, computational methods have to be used to understand their chemistry. The C$_5$N$^-$ anion is one of the largest (C,N)-bearing chains and, although there are several theoretical studies [1-3] that describe...
The presence of (micro)-plastics in different aquatic environments is a matter of world concern that has been gaining importance in recent years due to its potential impact on the environment and human health. (Micro)-plastics have been found in practically all types of water bodies and the presence of metals in these materials, either due to their manufacture or through adsorption processes,...
Alkyl nitrites (R$-$ONO, R$=$CH$_3$, n-C$_3$H$_7$, t-C$4$H$9$) have been widely studied due to the efficient photodissociation and formation of NO fragment.[1,2] The absorption spectra of all these molecules present two bands. A first band characterized by a clear vibronic structure, and a second more intense band which extends to the VUV energy reagion.[2,3] In this work, three different...
The detection of ionizing radiation is of vital importance in various branches of science, medicine, border security and environmental monitoring, among others. The development of new detection systems that have versatility of applications, of easy production and manipulation with viable costs has been one of the fields of application of many recent studies, namely in the field of neutron...
Several studies show that the combination of high-Z nanoparticles (NPs) and external radiotherapy (RT) leads to an increased radiation effect in tumoral cells without an increase of the patient dose [1,2]. Among the various elements with sensitizing potential, Au NPs have been the most studied due to the greater biocompatibility of gold. In this technique, Au NPs are incorporated inside tumor...
Due to its similarity with ammonia (NH$_3$) and because it has been observed in the interstellar medium,[1] methylamine (CH$_3$NH$_2$) has received considerable attention in the last decades. The molecular photodissociation of methylamine was studied using the pump-probe method with nanosecond laser pulses. The molecule was excited in the 198 $-$ 203 nm range, and the generated photofragments...
Every time an intervention is performed, the total (biopsy) or a portion (surgery) of normal and tumor tissue is retrieved and processed as Formalin Fixed Paraffin Embedded (FFPE) blocks for the diagnosis and after they are stored for safekeeping. These FFPE blocks contain precious information regarding the elemental composition of normal/tumor tissue that is not harvested because there is no...
Carlos M. R. Rocha1, Octavio Roncero2, Niyazi Bulut2,*, Piotr Zuchowski3, and Asunción Fuente4
1Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300-RA, Leiden, The Netherlands
2Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
3Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus...
The plasma divertor for the International Termonuclear Experimental Reactor (ITER) will have target plates made out of tungsten (W) [1]. The inevitable W contamination will emit characteristic radiation that depends on the specific charge state balance, electron temperature and density conditions. Therefore, the respective emission spectra can be used as real-time diagnostics of the fusion...
He hydrates present an intriguing and relatively unexplored systems. As they may have significant implications in fields such as planetary science, exploration of novel ice phases, such as ultra-low density ices or superionic water ice, and the development of innovative materials with distinct properties and applications, such as solid electrolyte in batteries, understanding their fundamental...
Aldehydes are very important trace gases for the physical chemistry of the troposphere mainly because they are directly emitted into the atmosphere or formed in situ from the photooxidation of organic compounds. In particular, the unsaturated aldehyde trans-2-methyl-2-pentenal (T2M2P) is emitted into the low atmosphere from several sources such as wildland fires, vegetation, and from some...
Raman spectroscopy (RS) is a highly-sensitive optical technique based on specific vibrations of molecules, which enables non-invasive and non-destructive monitoring of biospecimens present in tissues, revealing disease-prompted variations and allowing to differentiate healthy from malignant samples with high accuracy, sensitivity and specificity. Nevertheless, pigmented tissues are...
In this study, we investigated the elemental distribution of heavy metals in Zebrafish (Danio rerio) using an X-ray fluorescence system that relies on a gaseous detector. The primary objective was to analyze the presence and spatial distribution of heavy metals within the tissues of Zebrafish specimens. The employed X-ray fluorescence system, which incorporated a THCOBRA detector, allowed for...
Particleboard (PB) is produced using 50% to 75% recycled wood, with the possibility of reaching 100% recycled content, while Medium Density Fiberboard (MDF) is mostly made with virgin wood [1]. The presence of physical and chemical contaminants in wood waste may compromise its incorporation in recycling facilities. While physical contaminants as nails, joints, glass, textiles, etc., are easier...
Lipid membranes are highly complex and dynamic systems formed by hundreds of different types of lipids combined in specific ratios. Many pathological cells exhibit significant alterations in the lipid composition of their membranes when compared to healthy cells. For example, lipid profile singularities have been found in cancer, bacterial and viral infections and even in senescent cells...
An overview of our experimental program to detect QCD axions and axion-like-particles (ALPs) as possible candidates for dark matter (DM) using NMR techniques within the cosmic axion spin precession experiment (CASPEr) is presented [1]. ALPs are hypothetical particles that could also solve the strong CP violation problem, and it is predicted that the axion field would behave as a classical...
α-pinene is the most abundant monoterpene in the atmosphere and its oxidation yields to several oxygenated species that play a major role in the formation of secondary organic aerosols. α-pinene oxide (C$_{10}$H$_{16}$O) is generated from the reaction of ozone with α-pinene and has been shown to contribute to the formation of organosulfates under atmospheric conditions. Thus, understanding its...
In recent years, the COVID pandemic has garnered a great deal of attention, focusing mainly on the acute phase of the disease. However, this is only the beginning, as some patients continue to experience persistent symptoms, known as Post-COVID Condition (PCC), and an estimated 20% of those affected do not recover.The presence of this condition shows a number of obstacles, including the lack...
Molybdenum disulfide (MoS$_2$) is a two-dimensional (2D) semiconductor that has attracted significant attention due to its properties, such as a band gap energy dependent on the layers’number and a large specific surface area prone to chemical functionalization. These properties make 2D MoS$_2$ an excellent platform for optical sensing applications [1,2]. For example, the combination of...
The interaction of an electron with the dipole field of a neutral atom or molecule can lead to radiative photon emission by analogy with the familiar case of Nuclear Bremsstrahlung. This process is referred to as Neutral Bremsstrahlung and is possible even in noble atoms due to their induced dipole moment. Neutral bremsstrahlung in noble gases has been neglected in favor of excimer-based...
The development of light sources in the extreme ultraviolet (XUV) based on high harmonic generation has opened new avenues for the investigation of time-resolved photodynamics in cationic excited electronic states of polyatomic molecules. Here, an XUV pump-infrared (IR) probe scheme with femtosecond time resolution is employed to study the dynamics of dissociative ionization in methyl iodide...
Extreme Ultraviolet (EUV) table-top sources and soft to hard X-ray Free Electron lasers (XFELs) have opened a new era in science, providing ultrashort, coherent, and tunable pulses that are used to perform cutting-edge experiments in Atomic and Molecular physics, Condensed Matter Physics, Biology and Chemistry. However, most of the reported studies rely on linear light-matter interactions,...
Lipid cellular membranes constitute a common factor to all known Life on Planet Earth. It is this commonness, and yet their distinctions based on cell type, organism, or age[1] what makes them attractive targets for a wide range of treatments. Therefore, it is of paramount importance to understand how these ubiquitous structures react to different stimuli. Specifically, their mechanical...
In this Poster, we will present a proposal for a robust gamma radiation detector system for aerial mapping and radiation surveillance. It entails assembling and calibrating the detector using four high-resolution crystals and studying the effects of a VETO system. The detector will be equipped with real-time communication capabilities and AI algorithms for data analysis and source...
The photodissociation of dihalomethanes have received significant attention due to its role in producing pollutant species and ozone depletion.[1] Moreover, CH$_2$BrI presents an intricate structure of excited electronic states and a high bond selectivity. For instance, the A absorption band was attributed to C-I dissociation, while the A' band corresponds to C-Br bond fission.[2] However, the...
Attosecond probing of core-to-valence electronic transitions is a powerful tool for real-time observation of chemical dynamics.[1] Here, ultrafast extreme ultraviolet (XUV) transient absorption spectroscopy is employed to investigate the electronic and nuclear dynamics on small polyatomic iodinated molecules. The dynamics induced by one- or two-photon absorption using either few-femtosecond...
The kinetic study of neutral-neutral reactions in the gas phase at ultralow temperatures is undergoing a huge advancement over the last decades [1]. Such studies have exponentially increased due to the increasing number of new molecules detected in the interstellar medium (ISM), specially in the coldest regions (10-100 K). To model the chemistry occurring in these extreme environments, the...
Quantum Electrodynamics (QED) effects have been tested and measured in multiple systems, including free electrons, atomic and highly charged ions systems. Frequentist statistical analyses either point to a possible deviation from the theory prediction [1] of n = 2 → 1 transitions energy in two-electron systems with a dependency of Z^3, Z indicating the nuclear charge, or find no disagreement...
Argon gaseous detectors have been widely used in dark matter search and neutrino experiments over the last decade, owing to their unique ionization and scintillation characteristics. The primary and secondary scintillation in argon mainly result from the radiative de-excitation of singlet and triplet excimer states produced at gas pressures above 100 mbar. This well-known light production...
Medical imaging plays a crucial role in the diagnosis and treatment of various diseases and conditions. It allows healthcare professionals to visualize internal structures and processes of the body without the need for invasive procedures. Medical imaging techniques include x-ray, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound, among others. Position sensitive gas...
We have revisited and enlarged the vibrational analysis of diacetyl or 2,3-butanedione by means of state-of-the-art Raman spectroscopy [1] and quantum chemical computations. The Raman spectra were obtained previously only in condensed phases [2] and hence hindered low-energy vibrational modes were undetected. Here we measured the Raman spectra of diacetyl in all the gas and liquid phases and...
Gaseous neutron detectors are crucial tools to many scientific fields, as neutrons are used to probe matter, revealing structures and functions not accessible by other imaging means. 3He filled multi-wire chambers are being replaced by novel instruments coated with thick layers of boron,as 3He is now almost exclusively used for security applications. I will present a novel approach which...
Sulfur-containing heterocycles hoard a major scientific interest for its key role in natural and pharmaceutical products [1,2]. One of these compounds is 2-(2-pyridyl)benzo[b]thiophene, a heterobiarylic molecule whose structural insights are addressed here using computational methods and rotational spectroscopy.
Theoretical calculations have included density functional predictions (B3LYP-D3...
Para-aminobenzoic acid is a formerly used UVB filter that was found to react with the DNA when exposed to sunlight.[1] Molecular Dynamics (MD) and Umbrella Sampling simulations show that the neutral species of PABA binds favourably DNA by intercalation between two nucleobase pairs, while the binding of the anionic species is not feasible from the thermodynamic and kinetic points of view....
Imine-based molecular switches were recently developed, and so their properties remain largely unexplored[1]. Their potential to perform multi-step unidirectional rotations make them an important addition to the existing nanomotor toolbox[2]. Microwave rotational spectroscopy allows us to study the 3D structure of these molecules with great precision since we can relate the pattern of...
X-ray imaging is an invaluable tool for noninvasive analysis in many fields ranging from basic science to medicine and security. The development of low-dose large area imaging solutions still represents an important challenge for various applications.
One solution to the imaging of large areas lies in the development of novel computational imaging systems that can overcome the limitations...
Photoinduced electron transfer and charge transfer processes occurring in organic and inorganic materials are the cornerstone of technologies aiming at the conversion of solar energy into electrical energy and at its efficient transport. The early stages of these processes occur in the attosecond time scale, the natural time scale for electronic motion in atoms and molecules. Accessing this...
Conical intersections (CIs) are regions of the potential energy landscape of a molecule where the electronic and nuclear degrees of freedom become strongly mixed and the Born–Oppenheimer approximation breaks down. CIs are ubiquitous features in the photophysics and photochemistry of molecules and can be considered as “doorways” through which the photoexcited wavepacket is efficiently funneled...
Heritage science has one of its most interesting fields of research on the analysis of colour materials of what ancient Artworks are made of. In the last few years, special attention has been given to in-situ non-invasive approaches, such as the use of mapping elemental analysis (MA-XRF) and molecular analytical techniques (UV-Vis-NIR-FORS and hyperspectral imaging analysis).
In this work,...
please see attached
Solar-powered laser systems directly convert free broadband and incoherent solar radiation into narrowband and coherent laser radiation through an active medium, being considered as one of the most promising technologies in renewable energy research.
Our research group, led by Prof. Dr. Dawei Liang, was established more than a decade ago with the aim of substantially improving the...
For a long time, space was thought to be a hostile environment characterized by extreme conditions, in which the formation of any molecular system was highly unlikely, if not impossible. However, advances in three fundamental areas of molecular astrophysics (theoretical modeling, experimental laboratories, and observational missions), as well as, their joint effort are reponsible for more than...
Protonation and deprotonation processes in derivatives of aromatic systems play an important role in various areas of chemistry. The 'competition' between different centers to accept or donate a proton depends on a number of parameters, including electron density effects. This competition can result in the formation of different tautomers, each one having a different photophysical behavior....
In the present work, static and dynamic quantities of carbon dioxide (CO2) are studied by means of Raman spectroscopy in gas flows.
CO2 is a molecule of great importance in several current challenges, like characterization of exoplanets atmospheres, development of accurate climate models or synthesis of fuels through plasmas. Most of these problems involve non-local thermodynamic...
Many state-of-the-art optical readout micro-patterned gaseous detectors (MPGDs) are equipped with of standard Gas Electron Multipliers (GEMs), which are 50 μm thick. The COBRA_125, a 125 μm thick, triple-electrode MPGD has the potential to further increase the optical gain of these detectors: whereas in a GEM, the Electroluminescence light is only produced in the holes, the two independent...
Femtosecond time-resolved measurements have provided the timescales of bond breaking and bond forming processes for a wide range of chemical reactions. Some chemical reactions such as those that involve a collision with an atom or an electron, however, are very difficult to study by time resolved methods. This talk will focus on the reaction dynamics of radical cations far from equilibrium...
The ionization of molecules in the condensed phase is driven by the interactions established with the environment. In fact, for some aromatic molecules dissolved in water, the formation of the fully separated charges (cation+electron) has been found after exciting at the onset of their electronic absorption, well below the gas-phase ionization potentials.[1,2] By using transient absorption...
Azobenzene molecules present TRANS-CIS isomerization capabilities about the N=N bound, which can be induced with light. The TRANS conformation, naturally the most energetically stable at room temperature, can be converted into CIS conformation under the action of light, with the rate of TRANS-CIS-TRANS conversion for a given molecular system dependent on temperature and light, namely light...
Graphene quantum dots (GQD) are nanoparticles consisting of a single or several layers of graphene sheets whose thickness does not exceed 100 nanometers. GQD have become extremely popular in optoelectronics as nanocarriers for cancer therapy drugs and in bioimaging techniques, mostly due to their ease of preparation, biocompatibility and tunable absorption and emission properties...
Benzimidazole: One molecule - two photoreactions
Igor Reva
CIEPQPF, Department of Chemical Engineering, University of Coimbra,
Coimbra 3030-790, Portugal
Email: reva@eq.uc.pt
Monomers of benzimidazole trapped in an argon matrix at 15 K were characterized by vibrational spectroscopy and identified as 1H-tautomers exclusively. The photochemistry of matrix-isolated 1H-benzimidazole was...
The joint journey of rotational spectroscopy and radioastronomy is firmly pushing the frontiers of interstellar chemistry based on the detection of new molecules with ever-higher degrees of molecular complexity. However, for several families of compounds (e.g., carboxylic acids) the census of identified interstellar species has remained untouched for almost a quarter century. Herein, we...
One of the most fundamental questions in molecular dynamics is the dependence of a collision outcome on the relative orientation/alignment of the reactants, i. e. the stereodynamics of a collision process. For bimolecular gas phase reactions, it is possible to address this question by polarizing the reactants bond-axis and/or rotational angular momentum.[1-4]
Here, we will illustrate how...
For nearly a century, the role of quantum mechanical tunneling (QMT) in organic chemistry remained barely unrecognized. The interpretation of chemical selectivity has been done solely based on the classical paradigms of thermodynamic and kinetic control. However, it has recently been shown that these paradigms do not cover all aspects of chemical reactivity and QMT can also direct chemical...
Understanding the behaviour of endogenous therapeutic peptides (ETPs), short cationic peptides that have the ability to target and disrupt the pathological membranes, which typically contain a high concentration of anionic lipids, is crucial for the development of effective therapeutic strategies [1,2]. This study investigates multiple ETPs and their interaction with model lipid...
The application of THCOBRA based detectors for X-ray imaging has been studied. The optimization of detector performance is intrinsically related with the study of the gas mixture capable of providing the better image quality. When operating in gas flow mode with a gas mixture of Ne/CH$_4$ (95/5), a charge gain of $10^4$ was achieved, together with an energy resolution of about 22% (@ 8 keV),...
One-particle reduced density matrix (1RDM) functional theory is an alternative formalism to both density functional and wavefunction based methods. A pragmatic approach results in approximate functionals of the 1RDM in its diagonal form, that is, the use of natural orbitals and its occupation numbers as the fundamental variables, which define a natural orbital functional (NOF).
In this...
The current accuracy of atomic calculations is impressive, allowing us to explain and probe novel and extremely rich physical phenomena. In turn, novel experiments constantly allow us to validate and adjust our theories and calculations. The atomic data we can calculate encompasses many physical interactions, providing a wide range of fields with the necessary data for their own studies.
The...
Synchrotron light is a key instrument for the scientific approach towards a sustainable world, and the ever-growing communication among the different synchrotron facilities boosts their scientific and socio-economic impact at regional and global levels.
Over the past decade, the ALBA Synchrotron, the Spanish 3rd generation light source, has become an important pillar of the Spanish and...
Interactions between proteins and their solvent environment can be studied in a bottom-up approach using hydrogen-bonded biomolecule-solvent clusters. The ultrafast dynamics following UV-light-induced electronic excitation of the biomolecular chromophores, potential radiation-damage, and their dependence on solvation are important open questions. Specific and precise studies of the...
The Universe is molecularly rich [1]. Its chemical diversity and complexity are reflected by the more than 290 molecular species detected in the gaseous phase by means of radioastronomy [2] and the different solid-state phases in the form of dust grains [3]. The presence of the gas-phase molecules cannot be explained uniquely by reactions taking place in the gas phase but chemical reactions...
AMBER (Apparatus for Meson and Baryon Experimental Research) is an experiment located on the M2 beam line of CERN SPS. The understanding of the origin of the visible mass in the universe is one of its physics goals. It is known that the Higgs boson mechanism alone is not sufficient to explain the mass of a nucleon. Another phenomenon must interplay with it to explain the emergence of the...
NEXT (Neutrino Experiment with a Xenon TPC) is an experiment that searches for neutrinoless double beta decay in $^{136}$Xe using a high pressure xenon (HPXe) gas time projection chamber with electroluminescent (EL) amplification. The aim is to determine whether neutrinos are Majorana particles (i.e. they are their own antiparticle) or not, having huge implications in cosmology and particle...
Triatomic ultra-long Rydberg molecules are formed by the interaction of a Rydberg atom, an excited atom with an electron with high principal quantum number, and a polar molecule. The study of Rydberg molecules is motivated by its interesting properties [1-3], and possible applications in ultracold chemical reactions [4] or quantum simulations [5]. In this work, we investigate the electronic...
The search for dark matter is one of the highest priorities in contemporary modern particle physics roadmaps. Direct detection experiments employing noble liquid detectors are currently limited by the radioactivity from the detector materials, mostly from the specially radio-clean photomultiplier tubes (PMTs), contributing to the background at ~ 80% level. Large area avalanche photodiodes and...
\title{Non--Covalent Interactions in Carbon Dioxide Clusters: Comparison Between the Thiophenol--CO$_2$ and Benzylmercaptan--CO$_2$ Dimers Using Microwave Spectroscopy}
Carbon dioxide (CO$_2$), as a greenhouse gas causing global warming, has received great attention concerning its pollution effects and reactivity.\footnote{S. C. Peter, {\it ACS Energy Lett.\/}, {\bf 3}, 1557--1561...
The detection of particle dark matter (DM) remains an unresolved challenge in contemporary physics. The XENONnT experiment, located at the Laboratori Nazionali del Gran Sasso, in Italy, utilizes a multi-tonne liquid xenon time projection chamber to probe DM interactions. With an active target of 5.9 tonnes, low background, and keV-level threshold, XENONnT completes its science program with...
Laser-induced breakdown spectroscopy (LIBS) has emerged as a versatile technique for elemental analysis, offering high-resolution and real-time measurements, while being minimally destructive. This powerful analytical technique holds significant promise in various fields, including academia, technology, and industry. However, several challenges hinder its widespread adoption and limit its...
We present a new potential energy surface (PES) for the interaction between the Hydrogen molecule ion and the Helium atom in its electronic ground state. The PES of (H2+)He cluster is represented by two contributions: a polarization energy term due to the electric field generated by the molecular cation in the position of the polarizable He atom and dispersion-repulsion forces characterized by...
The sigmatropic isomerization reaction of previtamin D3 to vitamin D3, when encapsulated within a dimer of β-cyclodextrin, exhibits a 40-fold enhanced rate compared to its counterpart in an isotropic organic solution [1]. Despite several hypotheses, the exact mechanism by which β-cyclodextrin dimer catalyzes the reaction remained elusive.
We have conducted a rigorous investigation of...
The structures and energetics of Li+2-doped He clusters have been determined by means of evolutionary programming optimizations and classical molecular dynamics simulations [1]. The underlying interactions in the HeN Li+2 complexes are described by sum-of-potentials ab initio-based models [2]. The classical picture of the He atoms surrounding the cationic dimer shows a selective growth of the...
SH⁺ is a widespread molecular ion in diffuse interstellar clouds, and has also been detected in emission toward the Orion Bar photodissociation region (PDR). In warm and dense PDRs, SH⁺ is thought to form by exothermic reactions of S⁺ with vibrationally excited H2 (v>1). The viability of this hypothesis have been confirmed by theoretical simulations reaction which demonstrate that for...
The development of radiation detectors has seen significant advancements over the past decades, particularly in those relying on electroluminescence. Optical time projection chambers (OTPCs) have become the preferred choice in the field of direct dark matter searches (more specifically in WIMP searches), having also been considered for neutrino experiments. Dark matter experiments examples...
The computational simulation of biological processes is a complex task which requires the combination of different quantum and classical mechanical techniques. Moreover, these hybrid calculations are often performed within a dynamic framework to account for conformational sampling. In the case where the process under investigation takes place in a long-time scale, the application of enhanced...
Curcumin, a natural yellow pigment derived from the rhizome of turmeric (Curcuma longa L.), possesses significant biological properties. Nonetheless, its therapeutic potential is hindered by its limited bioavailability.[1] To address this challenge, and thus enhance the bioavailability and pharmacological efficacy of curcumin, one proposed strategy is the co-administration of curcumin with...
Understanding the formation of PoliAromatic Hydrocarbons (PAHs) can shed light on the origin of the prebiotic Earth and even on the origin of life.[1] Unfortunately, to date, the formation of organic compounds in space is a scarcely understood area.
In this arena, automated protocols for the identification of reaction mechanisms show great potential to aid in the learning of how PAHs are...
Given the recent detection of multiple neutron-star merger events, in particular the AT2017gfo observation, in which the ejection of hot and radioactive matter, termed kilonovae, was detected as an electromagnetic signal. It is critical to combine a more comprehensive description of nuclear and atomic properties with advanced astrophysical simulations in order to produce accurate predictions...
Host defense peptides (HDPs) are short cationic peptides that have a critical role in the innate immune response across all living organisms [1]. Their primary mode of action does not depend on protein receptors, but instead on their ability to target and disrupt the membranes of various pathogenic and pathological cells, such as those found in cancer, bacteria, or even our own senescent...
