Theory for vibrationally resolved two-photon circular dichroism spectra. Application to (R)-(+)-3-methylcyclopentanone.
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.
Lin
Na
N
Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, SE-10691 Stockholm, Sweden.
Santoro
Fabrizio
F
Rizzo
Antonio
A
Luo
Yi
Y
Zhao
Xian
X
Barone
Vincenzo
V
D002942:Circular Dichroism; D003517:Cyclopentanes / Q000737:chemistry*; D017785:Photons; D011789:Quantum Theory; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D014732:Vibration
C521405:3-methylcyclopentanone; D003517:Cyclopentanes