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Full–dimensional quantum molecular dynamics calculations of the rovibrationally mediated X 1 A ′ → 2 1 A ′ ′ transition of nitrous oxide
Author(s) -
Daud Mohammad Noh
Publication year - 2016
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25065
Subject(s) - rotational–vibrational spectroscopy , chemistry , transition dipole moment , atomic physics , photodissociation , absorption spectroscopy , dipole , molecular physics , quantum , absorption (acoustics) , dissociation (chemistry) , wavelength , spectral line , bound state , absorption band , excited state , physics , optics , organic chemistry , quantum mechanics , photochemistry , astronomy
A full dimensional time‐dependent quantum wavepacket approach is used to study the photodissociation dynamics of nitrous oxide for the X1 A ′→ 21 A ′ ′bound–bound transition based on new highly accurate potential energy and transition dipole moment surfaces. The computed 21 A ′ ′absorption spectra at room temperature are characterized by sharp vibrational structures that contribute slightly to the diffuse vibrational structures around the maximum peak at 180 nm of the first ultraviolet absorption band (from the contribution of 21 A ′ , 11 A ′ ′, and 21 A ′ ′states) of N 2 O. Transitions from different initial rovibrational states reveal that the sharp structures arise mainly from N 2 O bending vibrations, whereas, at higher temperatures, the N 2 O and NNO stretching vibrations are responsible for enhancing the intensity of the structures. At absorption wavelengths 166 nm and 179 nm, vibrational quantum state distributions of N 2 product fragments decrease monotonically with increasing vibrational quantum number v = 0, 1, 2. At 166 nm, rotational quantum state distributions of N 2 at fixed v = 0 and v = 1 display multimodal profiles with maximum peaks at j = 77 and j = 75, respectively, whereas, the distributions at the 179 nm absorption wavelength display bimodal profiles with maximum peaks at j = 73 and j = 71, respectively. Accordingly, the presence of rotationally hot N 2 from previous experimental and theoretical works in the first band strongly implies a significant influence of the 21 A ′ ′state in determining the final dissociation pathway of N 2 + O. © 2016 Wiley Periodicals, Inc.