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Ree J, Kim YH, Shin HK. Intramolecular vibrational energy redistribution in nucleobases: Excitation of NH stretching vibrations in adenine–uracil + H 2O. J Chem Phys 2022; 156:204305. [DOI: 10.1063/5.0087289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Redistribution of vibrational energy in the adenine–uracil base pair is studied when the base pair undergoes an intermolecular interaction with an overtone-bending vibration excited H2O(2[Formula: see text]bend) molecule. Energy transfer is calculated using the structural information obtained from density functional theory in the solution of the equations of motion. Intermolecular vibrational energy transfer (VET) from H2O(2[Formula: see text]bend) to the uracil–NH stretching mode is efficient and rapidly followed by intramolecular vibrational energy redistribution (IVR) resulting from coupling between vibrational modes. An important pathway is IVR carrying energy to the NH-stretching mode of the adenine moiety in a subpicosecond scale, the energy build-up being sigmoidal, when H2O interacts with the uracil–NH bond. The majority of intermolecular hydrogen bonds between the base pair and H2O are weakened but unbroken during the ultrafast energy redistribution period. Lifetimes of intermolecular HB are on the order of 0.5 ps. The efficiency of IVR in the base pair is due to near-resonance between coupled CC and CN vibrations. The resonance also exists between the frequencies of H2O bend and NH stretch, thus facilitating VET. When H2O interacts with the NH bond at the adenine end of the base pair, energy flow in the reverse direction to the uracil–NH stretch is negligible, the unidirectionality discussed in terms of the effects of uracil CH stretches. The energy distributed in the CH bonds is found to be significant. The IVR process is found to be nearly temperature independent between 200 and 400 K.
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Affiliation(s)
- J. Ree
- Department of Chemistry Education, Chonnam National University, Gwangju 61186, South Korea
| | - Y. H. Kim
- Department of Chemistry, Inha University, Incheon 22212, South Korea
| | - H. K. Shin
- Department of Chemistry, University of Nevada, Reno, Nevada 89557, USA
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Lee SK, Ree J. Isotope Effects on the Energy Flow and Bond Dissociations of Excited α‐Chlorotoluene in Collisions with
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. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sang Kwon Lee
- Department of Chemistry Education Chonnam National University Gwangju 61186 Korea
| | - Jongbaik Ree
- Department of Chemistry Education Chonnam National University Gwangju 61186 Korea
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