Exact quantum dynamical calculations of rovibrational spectra using massively parallel computers
Institution: | Texas Tech University |
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Department: | |
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.