Exact quantum dynamical calculations of rovibrational spectra using massively parallel computers

by Corey A. Petty

Institution: Texas Tech University
Year: 2014
Keywords: Exact quantum dynamics; Rovibrational spectra; Sparse-iterative eigensolver; HO2 system; Neon tetramer; Chemical physics; Physical chemistry; Computational chemistry; Molecular spectroscopy
Record ID: 2053124
Full text PDF: http://hdl.handle.net/2346/58938


We perform highly accurate rovibrational spectra calculations on the HO2 and Ne4 systems using ScalIT, an exact quantum dynamics software suite designed to perform such calculations across a massive number of computer processors in a straightforward manner. HO2 calculations are performed up to the dissociation threshold, corresponding to a total angular momentum value, J ≤ 130. A series of theory–based J–shifting (JS) schemes are also introduced and applied to a representative set of J values of HO2. The results are compared to both the previously mentioned exact values calculated, and experimentally derived vibrational-state-dependent JS results [J. Phys. Chem. A. 110, 3246, (2006)]. One of the introduced methods, the modified effective potential (modEP) scheme, outperforms all others in all regimes, and appears to be resistant to Coriolis-coupling effects. The modEP scheme is used as an analysis tool to shed structural insight on the dynamics of Coriolis-coupled eigenstate wave functions of HO2. The vibrational spectrum for Ne4 is calculated for all possible permutation inversion symmetries, and the physically real states are identified.