Computational investigation of energy transfer and line broadening for Ar + He collisions.

Potential energy curves for all states arising from the interaction of He with the 3p, 3p4s, and 3p4p configurations of Ar have been determined using high-level electronic structure calculations. The results have been used to examine collisional energy transfer probabilities and spectral line shape parameters (shifting and broadening rate coefficients). The main focus has been on states and transitions that are of relevance to optically pumped He/Ar laser systems.

The conformation of end-groups is one determinant of carotenoid topology suitable for high fidelity molecular recognition: a study of beta- and epsilon-end-groups.

Conformation affects a carotenoid's ability to bind selectively to proteins. We calculated adiabatic energy profiles for rotating the ring end-groups around the C6C7 bond and for flexing of the ring with respect to the polyene chain. The choice of computational methods is important.