Vibrational energy levels of the simplest Criegee intermediate (CH{sub 2}OO) from full-dimensional Lanczos, MCTDH, and MULTIMODE calculations
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States)
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)
Accurate vibrational energy levels of the simplest Criegee intermediate (CH{sub 2}OO) were determined on a recently developed ab initio based nine-dimensional potential energy surface using three quantum mechanical methods. The first is the iterative Lanczos method using a conventional basis expansion with an exact Hamiltonian. The second and more efficient method is the multi-configurational time-dependent Hartree (MCTDH) method in which the potential energy surface is refit to conform to the sums-of-products requirement of MCTDH. Finally, the energy levels were computed with a vibrational self-consistent field/virtual configuration interaction method in MULTIMODE. The low-lying levels obtained from the three methods are found to be within a few wave numbers of each other, although some larger discrepancies exist at higher levels. The calculated vibrational levels are very well represented by an anharmonic effective Hamiltonian.
- OSTI ID:
- 22493580
- Journal Information:
- Journal of Chemical Physics, Vol. 143, Issue 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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