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

Abstract

initio pair potential energy curve for the argon atom pair and thermophysical properties of the dilute argon gas. I. Argon-argon interatomic potential and rovibrational spectra. Molecular Physics, Taylor & Francis, 2009, 107 (20) An argon-argon interatomic potential energy curve was derived from quantum-mechanical ab initio calculations using basis sets of up to d-aug-cc-pV(6+d)Z quality supplemented with bond functions and ab initio methods up to CCSDT(Q). In addition, corrections for relativistic effects were determined. An analytical potential function was fitted to the ab initio values and utilized to compute the rovibrational spectrum. The quality of the interatomic potential function was tested by comparison of the calculated spectrum with experimental ones and those derived from other potentials of the literature. In a following paper the new interatomic potential is used to determine selected thermophysical properties of argon by means of quantum-statistical mechanics and the corresponding kinetic theory considering two-body and three-body interactions.

Communication: Ab initio Joule–Thomson inversion data for argon

“…Here we show that a seventh-order ab initio virial EOS for argon [20][21][22] gives rise to (high-temperature) JT inversion data in excellent agreement with the reference data set 5 up to the maximum inversion pressure. We also argue that the obtained JT inversion curves provide some insight into the range of applicability and high-density behavior of the truncated virial EOS.…”

“…Jäger et al have reported smooth temperaturedependencies of B 2 to B 7 in terms of fits (of Laurent polynomials in √ T ) to discrete B n data computed from ab initio two-body 21,22 and non-additive three-body potentials. 22 We use these fits to compute the JT inversion curve by solving…”

Role of three-body interactions in formation of bulk viscosity in liquid argon

“…Although more accurate ab initio pair potentials for argon have become available recently, 5,6 and other many-body contributions to inter-atom interaction can be calculated, 8 we use the same interaction as Nasrabad et al because, being able to predict accurately the phase diagram of argon, 16 it is computationally more efficient. Specifically, the ab initio pair interaction potential used in the present work is described by a function…”

“…Several experimental results obtained for argon at large pressures are better explained if a larger steepness, compared to Lennard-Jones, of argon-argon interaction potential at small inter-atomic separation distances is taken into account. 2,3 Accurate argonargon interatomic potentials have been calculated by direct ab initio quantum chemical calculations [4][5][6] or obtained by inversion of experimental data. 7 Moreover, many-body dispersion, exchange and induced polarization contributions to inter-atomic interactions are not small and noticeably influence thermodynamic properties of argon.…”

Predicting vapor liquid equilibria using density functional theory: A case study of argon

“…There is also significant emphasis on developing ab initio interatomic potential by using quantum chemical calculations and using it to predict bulk phase properties. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] The potential energy surface for a large number of configurations is generated to fit to the functional form of the force field. This approach is, however, limited to moderately sized molecules with limited conformational degrees of freedom as the computational cost increases significantly with the complexity of the molecule.…”