Some observations about quantum chemistry software GAUSSIAN

摘要

When laboratory study of some molecule is not available, one may plan to use data obtained from Quantum Chemistry software, such as GAUSSIAN, MOLPRO, NWCHEM, etc. For our investigation of cosmic molecules, we need reliable data for rotational and centrifugal distortion constants. For some molecules, we have obtained these data with the help of Quantum Chemistry software GAUSSIAN and compared them with those obtained from the laboratory studies. We have found that in some cases, the two sets of data are very close to each other whereas in some cases, they differ very much. As the laboratory measurements provide the most reliable data, one would like to use the GAUSSIAN data only when the laboratory data are available. Thus, an obvious question arises how to decide the reliability of GAUSSIAN data, when for that particular molecule no laboratory data are available. Further, when the laboratory data are available, no one would like to use the GAUSSIAN data.