State-to-state unimolecular reaction dynamics: Technical progress report. [Tetramethyldioxetane]

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6510402

Crim, F F

The combination of a selective excitation technique with spectroscopic product detection provides new experimental data on the dynamics of unimolecular reactions. In these experiments, direct excitation of overtone vibrations prepares highly vibrationally excited molecules and time-resolved spectroscopic detection monitors reaction products, often at the level of individual quantum states. We have studied the unimolecular decomposition of a nearly monoenergetic cyclic peroxide, tetramethyldioxetane, in a free-jet expansion and have directly measured its unimolecular decay rate. The vibrational overtone spectroscopy of the molecule in the expansion reveals previously unobserved inhomogeneous structure that is a significant factor in determining the lineshapes. Measurements on hydrogen peroxide in a low pressure gas have produced new spectroscopic and dynamic data, as well. We detect individual rotational states of the OH fragment from the vibrational overtone initiated unimolecular dissociation of HOOH and obtain vibrational overtone excitation spectra by varying the excitation laser wavelength. Two-photon vibrational overtone predissociation spectroscopic measurements can now be made. Different statistical models can be used to describe the unimolecular decay dynamics of small polyatomic molecules.

• Research Organization: Wisconsin Univ., Madison (USA)
• DOE Contract Number: AC02-80ER10755
• OSTI ID: 6510402
• Report Number(s): DOE/ER/10755-5; ON: DE87011200
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTIONS
CHEMILUMINESCENCE
DECOMPOSITION
DISSOCIATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
HETEROCYCLIC OXYGEN COMPOUNDS
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
HYDROXYL RADICALS
LUMINESCENCE
MOLECULES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
PEROXIDES
RADICALS
RESEARCH PROGRAMS
ROTATIONAL STATES
VIBRATIONAL STATES