Ab initiopotential energy curve for the helium atom pair and thermophysical properties of dilute helium gas. I. Helium–helium interatomic potential

Abstract

To cite this version:Eckhard Vogel, Eckard Bich, Robert Hellmann. Ab initio potential energy curve for the helium atom pair and thermophysical properties of the dilute helium gas. I. Helium-helium interatomic potential. Molecular Physics, Taylor & Francis, 2007, 105 (23-24) A helium-helium interatomic potential energy curve was determined from quantummechanical ab initio calculations. Very large atom-centred basis sets including a newly developed d-aug-cc-pV8Z basis set supplemented with bond functions and ab initio methods up to Full CI were applied. The aug-cc-pV7Z basis set of Gdanitz (J. Chem. Phys., 113, 5145 (2000)) was modified to be more consistent with the aug-cc-pV5Z and aug-cc-pV6Z basis sets. The diagonal Born-Oppenheimer corrections as well as corrections for relativistic effects were also calculated. A new analytical representation of the interatomic potential energy was fitted to the ab initio calculated values. In a following paper this potential model will be used in the framework of the quantum-statistical mechanics and of the corresponding kinetic theory to calculate the most important thermophysical properties of helium governed by two-body and three-body interactions.

Ab initiopotential energy curve for the neon atom pair and thermophysical properties for the dilute neon gas. II. Thermophysical properties for low-density neon

“…Even though the quality of the new neon ab initio potential of paper I [3] is somewhat inferior compared with our recent ab initio potential for helium [2], the calculated thermophysical properties are expected to be as accurate as the best experimental measurements at room temperature and more accurate than available experimental data far above and far below room temperature. In order to assess as accurately as possible the quality of the potentials considered in this paper, some of the experimental viscosity data from the literature were recalibrated with reference values derived from the new interatomic potential for helium [1,2]. 2 Quantum-mechanical calculation of thermophysical properties…”

“…Prerequisite for it was the determination of a state-of-the-art pair potential between two helium atoms [2].…”

Ab initiopair potential energy curve for the argon atom pair and thermophysical properties of the dilute argon gas. I. Argon–argon interatomic potential and rovibrational spectra

“…Recently, we demonstrated that for helium and neon highly accurate pair potentials can be calculated ab initio, i.e. purely from theory [1,2].…”

Erratum

“…Even though the quality of the new neon ab initio potential of paper I [3] is somewhat inferior compared with our recent ab initio potential for helium [2], the calculated thermophysical properties are expected to be as accurate as the best experimental measurements at room temperature and more accurate than available experimental data far above and far below room temperature. In order to assess as accurately as possible the quality of the potentials considered in this paper, some of the experimental viscosity data from the literature were recalibrated with reference values derived from the new interatomic potential for helium [1,2].…”

“…Prerequisite for it was the determination of a state-of-the-art pair potential between two helium atoms [2]. In order to establish a second standard for the calibration of high-precision measuring instruments at low density, we developed very recently a new interatomic pair potential for neon from high-level supermolecular ab initio calculations for a large number of internuclear separations R (paper I [3]).…”