Direct quantum chemistry covers a set of quantum chemical methods not using the Born–Oppenheimer representation. Direct quantum chemistry considers the motion of the nuclei and the electrons on the same time scales. The method therefore considers the molecular Hamiltonian as a whole without trying to solve separately the Schrödinger equation associated to the electronic molecular Hamiltonian. Though the method is non-adiabatic it is distinguishable from most non adiabatic methods for treating the molecular dynamics, which typically use the Born-Oppenheimer representation, but become non-adiabatic by considering vibronic coupling explicitly. Direct quantum chemistry is applied in the modelling of high-speed atomic collisions, where the nuclear motion may be comparable or faster than the electronic motion.
The group of Yngve Öhrn in Gainesville, Florida has been a pioneer in this field. He applied the method to the collision between two hydrogen atoms.
| This quantum mechanics-related article is a stub. You can help Wikipedia by expanding it. |
Famous quotes containing the words direct, quantum and/or chemistry:
“In Europe life is histrionic and dramatized, and ... in America, except when it is trying to be European, it is direct and sincere.”
—William Dean Howells (1837–1920)
“The receipt to make a speaker, and an applauded one too, is short and easy.—Take of common sense quantum sufficit, add a little application to the rules and orders of the House, throw obvious thoughts in a new light, and make up the whole with a large quantity of purity, correctness, and elegancy of style.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“...some sort of false logic has crept into our schools, for the people whom I have seen doing housework or cooking know nothing of botany or chemistry, and the people who know botany and chemistry do not cook or sweep. The conclusion seems to be, if one knows chemistry she must not cook or do housework.”
—Ellen Henrietta Swallow Richards (1842–1911)