title: TDDFT study on intramolecular hydrogen bond of photoexcited methyl salicylate.
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 OH⋯OC is decreased from 1.73 Å in the ground state to 1.41 and 1.69 Å in the excited S1 and S3 states. The increase of bond length for HO and CO group also indicates that in excited state the hydrogen bond OH⋯OC is strengthened. IR spectra show HO and CO stretching bands are strongly redshifted by 1387 and 67 cm(-1) in the excited S1 and S3 states comparing to the ground state. The excitation energy and the absorption spectrum show the S3 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 S1 and S3 states was predicted to be the π→π∗ mode.
authors.affiliation: State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China. Electronic address: tiandx@dlut.edu.cn.
authors.forename: Dongxu
authors.initials: D
authors.lastname: Tian
mesh_terms: D004583:Electrons; D006860:Hydrogen Bonding; D008958:Models, Molecular; D055668:Photochemical Processes; D011789:Quantum Theory; D012459:Salicylates / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D012459:Salicylates; C033069:methyl salicylate
keywords: Absorption spectra; Hydrogen bonded complex; Orbital transition; TDDFT; Vibrational redshift