title: Theory for vibrationally resolved two-photon circular dichroism spectra. Application to (R)-(+)-3-methylcyclopentanone.
abstract: A harmonic adiabatic approach in combination with density functional response theory for computing two-photon vibronically resolved circular dichroism spectra of chiral molecules is presented. It includes both Franck-Condon and Herzberg-Teller contributions and it takes fully into account frequency changes and Duschinsky effects. Model calculations have been performed for two dominant conformers of (R)-(+)-3-methylcyclopentanone in the gas phase. It is found that the Herzberg-Teller contribution can introduce a sign change in two-photon circular dichroism of a single excited electronic state of a conformer. The change survives after Boltzmann averaging, and it might be amenable to experimental verification. Interesting interference effects between Franck-Condon and Herzberg-Teller contributions are revealed and analyzed in detail. Results obtained within the more approximate and less computationally intensive linear coupling vibronic model are also given for comparison.
authors.affiliation: Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden.
authors.forename: Na
authors.initials: N
authors.lastname: Lin
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Santoro
authors.forename: Antonio
authors.initials: A
authors.lastname: Rizzo
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Xian
authors.initials: X
authors.lastname: Zhao
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
mesh_terms: D002942:Circular Dichroism; D003517:Cyclopentanes / Q000737:chemistry*; D017785:Photons; D011789:Quantum Theory; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D014732:Vibration
chemical_list: C521405:3-methylcyclopentanone; D003517:Cyclopentanes