QDMAP · Quantum dynamics of floppy systems beyond Coulomb interactions: magnetic and parity-violating effects

Chemistry is developed with the improvement of experimental and theoretical spectroscopy. A well-known approach for molecular vibration is based on harmonic oscillators, but it cannot be used for floppy systems. To analyze spectra of floppy systems, the exact quantum dynamics (QD) methodology based on a numerically ‘exact’ solution of the (ro)vibrational Schrödinger equation has been developed. It may appear that ro-vibrational spectroscopy is well established, based on the electronic Schrödinger equation with Coulomb interactions, but two additional effects that split molecular spectra remain: a) magnetic interactions due to nuclear spins, and b) parity-violation interactions, which is due to the electroweak force, causing tiny energy differences between enantiomers. The magnitude of a) is on the order of several tens of GHz (109 Hz), which is observable in the high-resolution spectrum. The magnitude of b) of a current target molecule is predicted about a few mHz (10-3 Hz), which is smaller than the current precision of the best experiments. The suggestion of new target molecules with large PV effects is required. These effects have been investigated for rigid systems, but never for floppy systems, where new coupling of ro-vibration and magnetic interactions, and strong enhancement of PV effects may be present. In this project, I investigate a) and b) of floppy systems by developing new QD methodology and by obtaining molecular properties (spin-rotational constant and PV energy), based on electron correlation theory. The objectives of this project are as follows: i) formulation, implementation, and application of QD with magnetic interaction for floppy systems, ii) theory development of QD for methanol-like molecules, and iii) QD application for chiral methanol-like molecules. This project provides the development of the exact quantum dynamics methodology which leads to a complete description of quantum nuclear motion in molecular systems.