Double resonance reactant preparation for state-to-state studies of unimolecular reactions

Technical Report · Fri Feb 01 04:00:00 EST 1991

OSTI ID:6070480

Rizzo, T R

These experiments use infrared-optical and optical-infrared double resonance spectroscopy to investigate the intramolecular dynamics of highly excited molecules. Application of the former approach to H{sub 2}O{sub 2} and NH{sub 2}OH indicates that statistical rate theories must incorporate the partial conservation of K rotational motion into their calculations. This method has also resulted in accurate values of the lowest energy bond dissociation energy for these two molecules: 17,054 {plus minus} 5 cm{sup {minus}1} for H{sub 2}O{sub 2} and 21,620 {plus minus} 20 cm{sup {minus}1} for NH{sub 2}OH. Moreover, these experiments reveal a barrier of 100--200 cm{sup {minus}1} for the recombination of two OH radicals on the lowest energy potential surface. Optical-infrared double resonance spectroscopy of high vibrational overtone levels allow us to measure the infrared spectrum of molecules at chemically significant energies. These spectra directly reveal the degree of localization of the wave functions prepared via vibrational overtone excitation. For molecules with sufficiently low density of states such as hydrogen peroxide, complete localization of 4 quanta of OH stretch excitation is possible. For molecules such as HONO{sub 2} and t-butyl hydroperoxide excited to the 4{nu}{sub OH} level, energy redistribution occurs rapidly on a 10 ns timescale and extends over the whole molecule. 8 refs.

• Research Organization: Rochester Univ., NY (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: FG02-88ER13965
• OSTI ID: 6070480
• Report Number(s): DOE/ER/13965-3; ON: DE91010733
• Country of Publication: United States
• Language: English

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