title: Thermal lens spectroscopy in liquid argon solutions: (Deltav = 6) C-H vibrational overtone absorption of methane.
abstract: A dual-beam thermal lens technique has been used to obtain the absorption spectrum of the (Deltav = 6) C-H stretch of liquid methane and methane in liquid argon solutions. The lowest concentration detected was 1 x 10(-3) (mole fraction) of CH(4) in liquid Ar with a continuous wave laser power of 20 mW. The thermal lens signal is linear with the mole fraction of methane up to 1 x 10(-2) but not for higher concentrations. Considering the system CH(4)-Ar as an ideal solution, the factors that contribute to the thermal lens signal were calculated as a function of the concentration of methane. A mechanism of energy transfer based on the gas-phase results could explain qualitatively the dependence of the magnitude of the signal on the mole fraction of methane.
authors.affiliation: Department of Chemistry & Biochemistry, Baylor University, Waco, Texas 76798, USA.
authors.forename: Juan G
authors.initials: JG
authors.lastname: Navea
authors.forename: Alfredo
authors.initials: A
authors.lastname: Lopez-Calvo
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Manzanares
mesh_terms: D000042:Absorption; D001128:Argon / Q000737:chemistry*; D008697:Methane / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods; D013696:Temperature; D014732:Vibration
chemical_list: D012996:Solutions; D001128:Argon; D008697:Methane