Speaker
Description
Estimation of the surface tension coefficients in the even-even nuclei could be performed due to connection of surface tension and nuclear rigidity [1]. The values of rigidities are connected with the mean squared deformations of nuclei [2]. The estimation of the surface tension coefficients in the even-even nuclei were presented in [3]. The coefficients $\sigma$ show great fluctuations: from $\sigma \approx$ 1.0÷1.8 (for 150<$A$<198) up to $\sigma$ ≈ 34 MeV/$\text{fm}^2$ (for $^{208}\text{Pb}$, $^{210}\text{Pb}$). The comparison of these values with the data on nuclear charge radii reveals the impact of the filled out neutron shell peculiarities on $\sigma$.
In the figures the calculated [3] surface tensions for Calcium and Zirconium isotopes together with the values of $r_0$ coefficients are shown. The surface tension in nuclei is highly influenced by the shell structure, especially of the neutron subshells near the surface: $(1d_{3/2})_n^4(1f_{7/2})^8_n$ for $^{48}\text{Ca}$ and $(1g_{9/2})^{10}(2d_{5/2})^6$ for $^{96}\text{Zr}$ . The highest $\sigma$ corresponds as well to the highest values of pressure $p$ (according to the Laplace formula $p \approx \frac{2 \sigma}{R}$). It is obvious that filling out two near neutron subshells leads to grow of pressure on the proton component of the nuclei and, as consequence, to decreasing of the charge radii.
For $^{208}\text{Pb}$ and $^{210}\text{Pb}$ the surface tension is close to the maximum among all even-even nuclei ($\sigma \approx$ 34 MeV/$\text{fm}^2$). It is approximately $0.75 \cdot 10^{20}$ higher than $\sigma$ for water at 20 $^\text{o}$C.
References
[1] A. Bohr // Dan.At.Fys.Medd. 22, #14, 7 (1952)
[2] S. Raman ea// At.Data & Nucl.Data Tabl. 78, 1 (2001)
[3] N.G. Goncharova //PEPAN 50,#5,532 (2019); N.G. Goncharova, A.P. Dolgodvorov //Moscow Univ.Bull.69#3(2014)
