Ab initio multiple spawning

The ab initio multiple spawning, or AIMS, method is a time-dependent formulation of quantum chemistry.

In AIMS, nuclear dynamics and electronic structure problems are solved simultaneously.

The AIMS method makes it possible to describe photochemistry from first principles molecular dynamics, with no empirical parameters.

The method has been applied to two molecules of interest in organic photochemistry - ethylene and cyclobutene.

For the photoinduced ring opening of cyclobutene, is it shown that the disrotatory motion predicted by the Woodward–Hoffmann rules is established within the first 50 fs after optical excitation.