Second virial coefficients of H2 and its isotopologues from a six-dimensional potential.
We employ path-integral Monte Carlo techniques to compute the second virial coefficient as a function of temperature for molecular hydrogen (H(2)), deuterium (D(2)), and tritium (T(2)), along with the mixed isotopologues HD, HT, and DT. The calculations utilize a new six-dimensional (6D) potential, which is derived by combining our previous high-quality ground-state 4D potential for the H(2) dimer with the 6D potential of Hinde. This new 6D potential is reduced to a set of 4D potentials by fixing the intramolecular coordinates at their expectation values for each temperature and isotopic combination. The results for H(2) are in good agreement with experimental data; the effect of the temperature dependence of the average bond length is only significant above approximately 1000 K. For D(2) and HD, the available experimental data are much more limited; our results agree with the data and provide reliable values at temperatures where no experimental data exist. For the species containing tritium, our results provide the only data available.
Interdisciplinary Laboratory for Computational Science, FBK-CMM and University of Trento, via Sommarive 18, I-38123 Povo (TN), Italy. garberoglio@fbk.eu
Giovanni
G
Garberoglio
Piotr
P
Jankowski
Krzysztof
K
Szalewicz
Allan H
AH
Harvey