PC Calculations Using Gaussian for Windows: A Complement to Laboratory Measurements on HCl

Abstract

The Gaussian for Windows program is applied to an ab initio calculation for HCl of structural and electronic properties which are often measured experimentally in undergraduate physical chemistry laboratories. Specifically, a detailed display of the effect of basis set size and calculation level on the bond length Re, the vibrational frequency omega(e), the dipole moment mu(e), and the polarizability alpha(e) is presented along with a potential energy surface scan at the HF, MP2, and QCISD(T) levels of theory. The agreement of the calculated values with experiment generally improves with increases in the basis set size, calculation level, and computational time. We have found that the easy access to such calculations on a laboratory PC encourages students to explore further the effects of different orbital choices and calculation levels, and to apply the Gaussian to other laboratory experiments.