Laser excitation spectra for matrix isolated IF: Observation of new low-lying electronic states

Publisher Website
Google Scholar
Abstract
Laser excitation of matrix isolated IF has been used to characterize three previously unobserved electronic states. Excitation at wavelengths longer than 535 nm resulted in emission from the metastable A′ 3Π(2) state. Vibrational analysis of the A′–X system gave an approximate value of Te(A′)=13 250 cm−1. The radiative lifetime of IF (A′) was found to be about 11 ms. Excitation of IF at wavelengths shorter than 475 nm produced a long-lived (τ=5 ms) fluorescence in the 720–1500 nm region. This emission originated from a low-lying electronic state (T00≂19 040 cm−1) and terminated on the v″=9 to 22 levels of the ground state. Laser excitation spectra, recorded by scanning the laser wavelength and monitoring this emission system, showed a progression of bands from 474 to 415 nm. Franck–Condon arguments show that the absorbing state is not the emitting state. The excitation spectra provided a T00 value of 21 100 cm−1 and a vibrational constant of 500 cm−1 for the absorbing state.