I-NoLLS least-squares fitting program.

Workshop on Wide-Amplitude Rovibrational Bound States in Polyatomic Molecules (2001)

Workshop on Rovibrational Bound States in Polyatomic Molecules (1999)

Molecular potential energy surfaces (PESs) are of central importance in molecular physics and many areas of physical chemistry. There is a great need for reliable molecular inter- and intramolecular potential energy surfaces (PESs) for the study of chemical reaction and photodissociation dynamics, energy exchange processes, surface scattering and the interpretation of spectroscopic effects. Theoretical computational methods for studying such problems have advanced enormously in recent years and often the major inaccuracies in calculations arise from uncertainties in the molecular potentials involved.

One powerful approach to determining such potentials is to determine the parameters of some assumed functional form by least-squares fitting. That is molecular (spectroscopic) properties predicted by a trial model potential function are compared with actual experimental observations and the parameters of the model optimised so that a good observed minus calculated fit is obtained.

This theme of determining accurate molecular PESs from spectroscopic data (including infrared, microwave, U.V. and visible) is central to a number of other interrelated components of our research:

- (i) Theoretical interpretation of molecular spectra;
- (ii) Calculation of vibration-rotation energy levels for small molecules;
- (iii) Intramolecular vibrational energy redistribution;
- (iv) Computational Chemistry using parallel computing methods;
- (v) Development of the methodology of fitting physical models to data.

The work on fitting physical models has resulted in a major new computer code, the I-NoLLS least-squares fitting program.

A Workshop on Rovibrational Bound States in Polyatomic Molecules was held in Aberdeen in April 1999.

This page last modified February 17th, 2009