title: [Low-frequency spectroscopy of four-photon scattering in aqueous solutions of biopolymers].
abstract: The novel method of nonlinear laser spectroscopy -- low frequency spectroscopy of four-photon scattering of laser radiation was applied to detect a considerable growth of ortho-H2O spin isomer and also H2O2 molecule concentration in a hydrate layer at the interface between water and DNA, denatured DNA molecules and alpha-chymotrypsin. Spectra of rotational resonances of ortho/para-H2O spin isomers were observed in aqueous solutions of different biopolymers and also in distilled water in the range from zero to 100 cm(-1) with the spectral resolution of 0.05-0.1 cm(-1). The fitting of four-wave mixing spectra shows notable growth of the H2O2 concentration and rotational line's amplitude by a factor of approximately 3 in DNA solutions due to denaturizing. Besides, we studied the four-photon scattering spectra of alpha-chymotrypsin aqueous solutions at protein concentrations between 0 and 20 mg/cm(3) in the range of +/- 7 cm(-1). We found that the velocity of sound in the protein aqueous solution measured by the shift of the Mandelstam-Brillouin scattering spectrum components was a cubic dependence on the protein concentration and reached the value of about 3000 m/s at 20 mg/cm(3).
authors.forename: A F
authors.initials: AF
authors.lastname: Bunkin
mesh_terms: D001704:Biopolymers / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007536:Isomerism; D007834:Lasers; D017785:Photons; D012996:Solutions / Q000737:chemistry*; D013057:Spectrum Analysis; D014867:Water / Q000737:chemistry*
chemical_list: D001704:Biopolymers; D012996:Solutions; D014867:Water; D004247:DNA; D006861:Hydrogen Peroxide