Laser-induced emission of CH₃O in solid argon

The A ²A₁ - X ²E fluorescence of CH ₃O in solid Ar in the wavelength range 310-420 nm has been studied either by simultaneous laser photolysis and excitation of CH₃ONO in the Ar matrix or by laser excitation of the products deposited from the reactions of microwave-discharged CF₄ with CH₃OH diluted by Ar. The spectrum showed an extensive progression in C-O stretching (v ₃). The zero-phonon lines of ¹²CH₃O and ¹³CH₃O yielded unambiguous vibrational assignments with v₀₀ = 31 291, ω″_e = 1051, and ω″_ex″_e = 6.5 cm^-1 for ¹²CH₃O. Observation of several weak combination bands also yielded v″₂ = 1356, v″₄ = 2758, and v″₅ = 1406 cm^-1. The laser excitation spectra in the 273-322 nm region also exhibited an intense progression in C-O stretching with ω′_e = 657 and ω′_ex′ _e = 4.4 cm^-1 for ¹²CH₃O. Additional wave numbers v′₂ = 1308 and v′₅ = 1410 cm ^-1 were also obtained from the combination bands.