Total internal partition sums for molecules of astrophysical interest

Total internal partition sums (TIPS) are calculated for several molecules, which are abundant in non-terrestrial planetary atmospheres. For all molecules, calculations are performed for the most abundant isotopic species. Partition sums for lesser abundant isotopomers of several molecules are determined as well. The calculations are made for temperatures between 70 and 300 K. The resulting TIPS are fit to a polynomial expression, which is fourth order in temperature. The methods of calculation of the TIPS, the convergence, and the quality of the polynomial fits for each isotopomer are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.