Electronic Structure Determination from High-Resolution Data

Professor Stanton and his group develop new theoretical methods in chemistry and implement them in computationally efficient computer programs, applying the methods to the solution of interesting chemical and spectroscopic problems. They work closely with several experimental groups in the United States and abroad whose studies often serve as motivation or inspiration for the Stanton group's work.

Most recently, the group has been active in the study of "interstellar molecules" and the chemistry that takes place in the outer reaches of space between the stars. Far from void, these spaces are thinkly sprinkled with the debris of novae and supernovae, and the molecules observed or thought to exist in this interstellar medium are of interest both as primitive material for future stars and as carriers of information about the composition of past stars.

The observations consist of infrared and microwave spectra of the molecules of interest. To interpret these spectra accurately, the spectra produced by such molecules must be calculated theoretically from first principles, which is what the Stanton group does. In particular, they can calculate highly accurate anharmonic force fields for the molecules, required for rigorous analysis of microwave spectra, and they can simulate the electronic spectra of the molecules to predict the mix of molecules seen in observations.

Among the molecules currently under study are the HOONO system and the NO3 radical. Recent calculations of cubic and quartic force fields of nitric acid and its HOONO isomers, carried out on the Lonestar cluster, were presented with great impact at the American Chemical Society annual meeting held in Philadelphia in 2004, and several publications are forthcoming on those calculations.