Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 3 of 3

Full-Text Articles in Chemistry

Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo Aug 2015

Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

Accurate vibrational energy levels of the simplest Criegee intermediate (CH2OO) 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 …


Kinetic Isotope Effect Of The ¹⁶O+³⁶O₂ And ¹⁸O+³²O₂ Isotope Exchange Reactions: Dominant Role Of Reactive Resonances Revealed By An Accurate Time-Dependent Quantum Wavepacket Study, Zhigang Sun, Dequan Yu, Wenbo Xie, Jiayi Hou, Richard Dawes, Hua Guo May 2015

Kinetic Isotope Effect Of The ¹⁶O+³⁶O₂ And ¹⁸O+³²O₂ Isotope Exchange Reactions: Dominant Role Of Reactive Resonances Revealed By An Accurate Time-Dependent Quantum Wavepacket Study, Zhigang Sun, Dequan Yu, Wenbo Xie, Jiayi Hou, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

The O + O2 isotope exchange reactions play an important role in determining the oxygen isotopic composition of a number of trace gases in the atmosphere, and their temperature dependence and kinetic isotope effects (KIEs) provide important constraints on our understanding of the origin and mechanism of these and other unusual oxygen KIEs important in the atmosphere. This work reports a quantum dynamics study of the title reactions on the newly constructed Dawes-Lolur-Li-Jiang-Guo (DLLJG) potential energy surface (PES). The thermal reaction rate coefficients of both the 18O + 32O2 and 16O + 36O2 reactions obtained using the …


Note: Improved Line Strengths Of Rovibrational And Rotational Transitions Within The X3Σ⁻ Ground State Of Nh, James S.A. Brooke, Peter F. Bernath, Colin M. Western Jan 2015

Note: Improved Line Strengths Of Rovibrational And Rotational Transitions Within The X3Σ⁻ Ground State Of Nh, James S.A. Brooke, Peter F. Bernath, Colin M. Western

Chemistry & Biochemistry Faculty Publications

Recently, a line list including positions and transition strengths was published for the NH X3Σ rovibrational and rotational transitions. The calculation of the transition strengths requires a conversion of transition matrix elements from Hund’s case (b) to (a). The method of this conversion has recently been improved during other work on the OH X2Π rovibrational transitions, by removing an approximation that was present previously. The adjusted method has been applied to the NH line list, resulting in more accurate transition strengths. An updated line list is presented that contains all possible transitions with v′ and …