The response of diatomic chemical intermediates to electric and magnetic fields.

摘要

A high-resolution spectroscopic investigation has been performed in order to determine permanent electric and magnetic dipole moments of gas-phase transition-metal containing molecules. Permanent electric dipole moments for FeC, RuC, MoC and TiO were determined via optical Stark spectroscopy, while magnetic studies were performed on TiO using optical Zeeman spectroscopy. Time-of-flight (TOF) mass spectrometry and transient frequency modulation (TFM) techniques were developed to supplement the high-resolution work.;Laser ablation and molecular beam production methods were developed to prepare the ephemeral species for spectroscopic inquiry. High-resolution laser-induced fluorescence (LIF) field-free, Stark and Zeeman detection techniques were implemented to record the response of the molecules to external electric and magnetic fields. An effective Hamiltonian approach incorporating extensive use of angular momentum theory was utilized to analyze and predict molecular spectra, resulting in quantitative measurements of permanent dipole moments, magnetic hyperfine, lambda doubling and electric quadrupole coupling parameters.;The results of the high-resolution experiment show that theoretical predictions of other research groups fail to accurately predict permanent electric and magnetic dipole moments, especially when mixing between molecular states is significant. Despite the inadequacy of some current theoretical calculations, results of the high-resolution experiment can be interpreted to pinpoint shortcomings in theoretical approach.;A well-designed experiment is necessary to determine chemical structure and properties. Stark and Zeeman techniques used to measure permanent electric and magnetic dipole moments glean periodic trends in chemical bonding and garner insight into the nature of the metal-ligand bond through investigation of the chemically relevant valence electrons. The connection between experiment and chemical nature is most illuminated when quantitative experimental results are coupled to molecular orbital correlation diagrams and theoretical calculations, thus creating the symbiosis between experiment and theory desired by all scientific studies.