Three-level and four-level infrared-infrared double resonance spectroscopy in CH[sub 3]F

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7114294

Song, Quan

A series of three-level and four-level infrared-infrared (IR-IR) double resonance experiments have been carried out to study saturation spectroscopy, to determine the various features of collisionally-induced transitions, to determine the vibration rotation energies of a highly excited vibration state, and to measure the precise frequencies of rovibrational transitions in methyl fluoride. In these experiments, either a fundamental rovibrational transition, or a hot band transition in the [nu][sub 3] vibrational mode of CH[sub 3]F was pumped by a CO[sub 2] laser coincidence, while rovibrational transitions, involving excitation of either the [nu][sub 3] or the [nu][sub 6] vibrational mode, were probed by an infrared microwave sideband laser system. Dynamic Stark splitting (Rabi splitting) has been observed in three-level IR-IR double resonance in CH[sub 3]F. The line shape has been fit to theoretical expressions that were derived from a semi-classical treatment of a three-level system. A very good agreement between theory and experiment has been obtained. Rotation and vibration-rotation transitions in CH[sub 3]F induced by collision with foreign gases such as H[sub 2], He, Ar, Xe or isotopically-labeled CH[sub 3]F have been studied by the method of four-level IR-IR double resonance. All of the observed transitions obey selection rules. It has been found that Ar or Xe can collisionally-induce direct vibrational transitions in CH[sub 3]F more readily than CH[sub 3]F itself. Classical elastic scattering theory has been used to calculate one-dimensional collision kernels with Lennard-Jones and Buckingham-Slater intermolecular potential functions. Initial velocity dependence of the collisionally-induced rotational energy transfer in CH[sub 3]F has been studied.

• Research Organization: Michigan State Univ., East Lansing, MI (United States)
• OSTI ID: 7114294
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ARGON
CARBON DIOXIDE LASERS
COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
FLUORINATED ALIPHATIC HYDROCARBONS
GAS LASERS
GASES
HALOGENATED ALIPHATIC HYDROCARBONS
HELIUM
HYDROGEN
INFRARED SPECTRA
LASERS
METHYL FLUORIDE
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
RARE GASES
ROTATIONAL STATES
SPECTRA
VIBRATIONAL STATES
XENON