Second virial coefficients for He4 and He3 from an accurate relativistic interaction potential

Path-integral calculation of the fourth virial coefficient of helium isotopes

“…i with k = 1, 2, 3, 4 are the coordinates of independent P-bead ring polymers, r (k) i with k = 5, 6 are the coordinates of independent 2P-bead ring polymers and mass m/2, r (7) i are the coordinates of a 3P-bead ring polymer and mass m/3, and r (8) i are the coordinates of a 4P-bead ring polymer and mass m/4.…”

“…For helium, in 2012 Cencek et al 5 reported values of B(T ) of unprecedented accuracy calculated from a pair potential that incorporated higher-order effects (adiabatic correction to the Born-Oppenheimer approximation, relativistic effects, quantum electrodynamics). The potential was further improved in 2017 by Przybytek et al, 6 and still further in 2020 by Czachorowski et al 7 The 2020 work reports B(T ) for both 4 He and 3 He with uncertainties 5-10 times smaller than the uncertainties obtained by Cencek et al 5 This accuracy results both from the highly accurate pair potential and from the fact that an exact quantum calculation of B(T ) is possible via a phase-shift method. 8 For the third virial coefficient C(T ), no exact solution is known, but the fully quantum result can be approached numerically with the path-integral Monte Carlo (PIMC) method.…”

“…In this work, we use state-of-the-art pair 7 and three-body 13 potentials to compute D(T ), fully incorporating exchange effects in our PIMC calculations. We also provide the first rigorous calculations of D(T ) for 3 He, and provide uncertainty estimates that include not only statistical uncertainty but also the contribution of uncertainties in the potentials.…”

Dipole-dipole polarizability of the cadmium $\mathbf{^1S_0}$ state revisited

“…During the last decades quantum-chemical methods have improved dramatically and in many aspects are now able to match or even surpass the quality of experimental findings of various fundamental atomic and molecular properties [1][2][3][4] . This is especially the case for atomic and molecular dipole-dipole polarizabilities α (from now on α is just called the polarizability).…”

Acoustic measurement of the triple point of neon T Ne and thermodynamic calibration of a transfer standard for accurate cryogenic thermometry

“…Sensitivity of results to the choice of h. We fit equation(1) to combined data from run 1 and run 2 twice; once fixing A −1 assuming h = 0.39 and once fixing A −1 assuming h = 0.34. The values of A 1 were fixed by theory[26]. The last row of the table is the theoretical value of A 2[27].…”