Time-resolved spectroscopy on the excited electronic states of NO2 in the neighborhood of 454.6 nm

Abstract

The time‐resolved excitation spectrum and the time‐resolved fluorescence spectrum were measured by using a pulsed, tunable dye laser (Δt=4 ns, Δλ=3.5 pm) and a pulse‐gated photon counter (Δt=4 ns). The three kinds (one ²B₁ and two ²B₂) of the excited electronic states of NO₂ were resolved in the 454.3–454.8 nm region. Sharp Q and R rotational lines of the transition to the (0, 8, 0) vibrational level of the ²B₁ excited electronic state appeared in the time‐resolved excitation spectrum monitored through the ν₂ band fluorescence. Meanwhile sharp lines and a continuum band were observed in both excitation spectra monitored through the ν₁ and ν₂ band fluorescence. These sharp lines could be assigned to the transition to the (1, 10, 0) vibrational level of the ²B₂ state. The continuum band seems to be dominantly composed of many rotational lines to the perturbed ²B₂ states.