Second virial coefficients of alkali vapours

Based on the ab initio calculations of Bertoncini et al, (J. Chem. Phys.; 52:5112 (1970)), on the triplet state of LiNa, the present authors proposed a Sato-type anti-Morse potential for the alkali dimers and used this in the calculation of Bsup((3))(T) [the triplet state contribution to the second virial coefficient] of alkali vapours. In this note the potential is compared with those of other workers in the calculation of Bsup((3))(T) and the second virial coefficients of all the alkali vapours are calculated over a wide range of temperature using the Morse and Rydberg potentials for the ground state and the anti-Morse potential for the triplet state of the dimers. (U.K.)