title: Analytic calculations of hyper-Raman spectra from density functional theory hyperpolarizability gradients.
abstract: We present the first analytic calculations of the geometrical gradients of the first hyperpolarizability tensors at the density-functional theory (DFT) level. We use the analytically calculated hyperpolarizability gradients to explore the importance of electron correlation effects, as described by DFT, on hyper-Raman spectra. In particular, we calculate the hyper-Raman spectra of the all-trans and 11-cis isomers of retinal at the Hartree-Fock (HF) and density-functional levels of theory, also allowing us to explore the sensitivity of the hyper-Raman spectra on the geometrical characteristics of these structurally related molecules. We show that the HF results, using B3LYP-calculated vibrational frequencies and force fields, reproduce the experimental data for all-trans-retinal well, and that electron correlation effects are of minor importance for the hyper-Raman intensities.
authors.affiliation: Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
authors.forename: Magnus
authors.initials: M
authors.lastname: Ringholm
authors.affiliation: Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, AlbaNova University Center, S-10691 Stockholm, Sweden.
authors.forename: Radovan
authors.initials: R
authors.lastname: Bast
authors.affiliation: Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
authors.forename: Luca
authors.initials: L
authors.lastname: Oggioni
authors.affiliation: Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekström
authors.affiliation: Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø - The Arctic University of Norway, 9037 Tromsø, Norway.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ruud
mesh_terms: D000465:Algorithms; D007536:Isomerism; D011789:Quantum Theory; D012172:Retinaldehyde / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D012172:Retinaldehyde