Some observations about the MOLSCAT

Abstract

For calculation of cross sections for collisional transitions between rotational levels in a molecule, a computer code, MOLSCAT has been developed by Hutson \& Green (1994). For the transitions between rotational levels in H$_2$CS due to collisions with He atom, we have calculated cross sections under the CS approximation. In the MOLSCAT, there is provision to input more than one values of total energies. Here, for example, we are interested in the cross sections for total energy 11 cm$^{-1}$. The calculations have been done for the single energy 11 cm$^{-1}$ and for eight combinations, having energies (11, 12), (12, 11), (10, 11), (11, 10), (11, 12, 13), (9, 10, 11), (10, 11, 12), (9, 10, 11, 12, 13) cm$^{-1}$. We have found that the cross sections for 11 cm$^{-1}$, in general, differ from one another in all the 9 calculations. The reason for the difference in the results appears that the MOLSCAT uses the intermediate data of calculations for one energy, in the calculations for other energies. Under such circumstances, the possible suggestion can be to run the MOLSCAT for a single energy at a time.