title: Anharmonicity Effects in IR Spectra of [Re(X)(CO)3(α-diimine)] (α-diimine = 2,2'-bipyridine or pyridylimidazo[1,5-a]pyridine; X = Cl or NCS) Complexes in Ground and Excited Electronic States.
abstract: Infrared spectra of [Re(X)(CO)(3)(α-diimine)] (α-diimine = 2,2'-bipyridine, X = Cl, NCS, or pyridylimidazo[1,5-a]pyridine, X = Cl) in the ground and the lowest triplet electronic states were calculated by a global hybrid density functional going beyond the harmonic level by means of second-order vibrational perturbation theory (VPT2) and including bulk solvent effects by the polarizable continuum model (PCM). The full-dimensionality (FD) VPT2 is compared with the reduced-dimensionality (RD) model, where only selected vibrational modes are calculated anharmonically. The simulated difference IR spectra (excited state minus ground state) in the ν(CO) region closely match experimental time-resolved infrared (TRIR) spectra. Very good agreement was also obtained for ground-state spectra in the fingerprint region. In comparison with the harmonic simulated spectra, the calculated anharmonic frequencies are closer to experimental values and do not require scaling when the B3LYP functional is used. Several spectral features due to combination bands have been identified by VPT2 simulations in the ν(CO) spectral region, which are of importance for a correct interpretation of TRIR experiments.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3, 182 23 Prague 8, Czech Republic.|Department of Inorganic Chemistry, University of Chemistry and Technology , Prague, Technická 5, 166 28 Prague 6, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Kvapilová
authors.affiliation: J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3, 182 23 Prague 8, Czech Republic.|Queen Mary University of London, School of Biological and Chemical Sciences , Mile End Road, London E1 4NS, United Kingdom.
authors.forename: Antonín
authors.initials: A
authors.lastname: Vlček
authors.affiliation: Scuola Normale Superiore, Piazza dei Cavalieri , 7 I-56126 Pisa, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
authors.affiliation: Physics Department, and International Centre for Quantum and Molecular Structures, Shanghai University , 99 Shangda Road, Shanghai, 200444 China.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Biczysko
authors.affiliation: J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Záliš
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D012211:Rhenium / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014732:Vibration
chemical_list: D009942:Organometallic Compounds; D011725:Pyridines; D015082:2,2'-Dipyridyl; D012211:Rhenium; C023666:pyridine