FTS-LIF-I PRECISE DESCRIPTION OF A MOLECULE STATE : THE GROUND STATE OF THE IODINE MOLECULE

Abstract

The record with a High Resolution Fourier Transform Spectrometer (FTS) of Laser Induced Fluorescence Spectra (LIF) leads to a precise description of molecular states. This is checked using various exciting lines (501.7, 514.5 nm of $Ar^{+}$ and 520.8, 530.8 of $Kr^{+}$). This samples the whole set of vibrational levels of the iodine X state from $v^{\prime\prime} =0$ to the dissociation limit, and rotational levels from $J^{\prime\prime}=0$ to 150 .The R.M.S. deviation between calculated and measured lines is of the order of $0.001 cm^{-1}$ and for intense lines the intensities are known within a relative error of a few percent. Then with this precise description it is possible to know the position and transition moment of the $10^{6}$ possible losing lines of the iodine laser from 0.5 to 1.35 $\mu m$ or to calculate a priori their related gain. Also the investigation of the last vibrational levels is important to describe the molecule near its dissociation limit.