title: Solvent effects on resonant first hyperpolarizabilities and Raman and hyper-Raman spectra of DANS and a water-soluble analog.
abstract: The two-photon-resonant first hyperpolarizabilities associated with hyper-Rayleigh and hyper-Raman scattering are reported for 4-dimethylamino-4-nitrostilbene in 1,4-dioxane, dichloromethane, acetonitrile, and methanol, and for an ionic analog, 4-N,N-bis(6-(N,N,N-trimethylammonium)-hexyl)amino-4-nitrostilbene dibromide in methanol and water. Resonance Raman and hyper-Raman excitation profiles are also measured and modeled. The resonance Raman and hyper-Raman spectra show very similar relative intensities which do not vary much as the excitation frequency is tuned across the lowest-energy strong linear absorption band, suggesting that a single resonant electronic state dominates the one- and two-photon absorptions in this region. The absorption, resonance Raman, and hyper-Raman profiles can be simulated reasonably well with a common set of parameters. The peak resonant (absolute value of beta)2, measured by hyper-Rayleigh scattering, varies by about 50% over the range of solvents examined and shows a weak correlation with the linear absorption maximum, with the redder-absorbing systems exhibiting larger peak hyperpolarizabilities. The experimental hyper-Rayleigh intensities are higher than those calculated, possibly reflecting contributions from nonresonant electronic states.
authors.affiliation: School of Natural Sciences, University of California, Merced, Merced, California 95340, USA.
authors.forename: Lian C T
authors.initials: LC
authors.lastname: Shoute
authors.forename: Han Young
authors.initials: HY
authors.lastname: Woo
authors.forename: Doojin
authors.initials: D
authors.lastname: Vak
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
authors.forename: Anne
authors.initials: A
authors.lastname: Myers Kelley