Gaussian 98 is the latest in the Gaussian series of electronic structure programs. Designed to model a broad range of molecular systems under a variety of conditions, it performs its computations starting from the basic laws of quantum mechanics. Gaussian 98 is used by chemists, physicists and engineers for research in established and emerging areas of chemical interest, studying molecules and reactions of definite or potential interest, including both stable species and compounds which are difficult or impossible to observe experimentally: short-lived intermediates, transition structures and the like. 

Gaussian 98 can predict energies, molecular structures, vibrational frequencies-along with the numerous molecular properties that are dervied from these three basic computation types-for systems in the gas phase and in solution, and it can model them in both their ground state and excited states. Chemists apply these fundamental results to their own investigations, using Gaussian 98 to explore chemical phenomena like substituent effects, reaction mechanisms, and electronic transitions.