Single vibronic level fluorescence emission spectroscopy and radiative lifetimes of H2CO(?1A2):4 and 41

Abstract

Intensity distributions of the fluorescence emission bands from the two lowest vibrational levels of H₂CO(?¹A₂) have been determined in the wavelength range of 360–460 nm. All of the emission bands observed are well characterized by the Δν₂ progressions built on Δν₄= odd, and the intensity distribution maxima of the 2⁰_m4⁰_n and 2⁰_m4¹_n progressions occur at m =1, n=1 and m=1, n=2, respectively. From the thermalized intensity distribution data extrapolated to the high pressure limit of n‐C₄H₁₀ as a buffer gas, the ratio of the radiative lifetimes for the two single vibronic levels, 4¹ and 4⁰, has been obtained as 0.68±0.12, which agrees well with the theoretical values calculated by either Barnhart and Strickler or Miller and Lee.