Laser Magnetic Resonance applied to excited States of Iodine and to the Fine structure Transition in the electronic Groundstate of Iodine Monoxide

Abstract

This thesis describes an investigation of the spectra of iodine and iodine monoxide in the region about 2100cm-1. For this study, the CO Faraday Laser Magnetic Resonance Spectrometer at Bonn was used. For the first time a CO­v=(1->0) laser was used in such an experiment. <br /> For the iodine atoms, several transitions in the region between 2056cm-1 and 2103cm-1 were recorded. In order to explain these observations, a theo retical model was developed including the spin­orbit interaction, the mag netic dipole and electrostatic quadrupole hyperfine interactions and the Zee man effect. The contributions by the electronic configuration were included using the central field approximation. Afterwards this picture was con verted into matrix representations for LS , JcK; s-coupled and JcK; s- decoupled vector coupling schemes.<br /> A program for fitting the LMR spectra to the theoretical model was written and tested on a known transition between excited states of chlorine. In the course of this, a fault in the previous analysis was found and corrected. For the newly recorded data of iodine atoms, a complete analysis of the transitions was performed for three transitions. Thus, accurate g-factors and hyperfine parameters were obtained. <br /> The purpose of the investigation of iodine monoxide was the determination of the finestructure splitting of the vibronic groundstate. Spectra in the region 2064...2103cm-1 were recorded. They have to be attributed to IO for their chemical characteristic and their rich hyperfine structure. Due to the latter, no lines are resolved and an analysis via a least squares fit becomes impossible. An alternative approach by a simulation of the spectra was attempted and the spin­orbit splitting was found to be of the order of 2073.5(1.0)cm-1 . Although the accuracy of this value is far from being satisfying, it still resembles the first direct measurement of the splitting and improves the previously known value of 2091(40)cm-1 considerably.