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Indexed by:期刊论文

Date of Publication:2014-02-24

Journal:SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

Included Journals:SCIE、EI、PubMed、Scopus

Volume:120

Page Number:529-533

ISSN No.:1386-1425

Key Words:Hydrogen bonded complex; Orbital transition; Absorption spectra; Vibrational redshift; TDDFT

Abstract:The equilibrium geometries, IR-spectra and transition mechanism of intramolecular hydrogen-bonded methyl salicylate in excited state were studied using DFT and TDDFT with 6-31++G (d, p) basis set. The length of hydrogen bond O-H center dot center dot center dot O=C is decreased from 1.73 angstrom in the ground state to 1.41 and 1.69 A in the excited S-1 and S-3 states. The increase of bond length for H-O and C=O group also indicates that in excited state the hydrogen bond O-H center dot center dot center dot O=C is strengthened. IR spectra show H-O and C=O stretching bands are strongly redshifted by 1387 and 67 cm(-1) in the excited S-1 and S-3 states comparing to the ground state. The excitation energy and the absorption spectrum show the S-3 state is the main excited state of the low-lying excited states. By analyzing the frontier molecular orbitals, the transition from the ground state to the excited S-1 and S-3 states was predicted to be the pi -> pi* mode. (C) 2013 Elsevier B.V. All rights reserved.