Spectroscopy and scattering dynamics of hydroxyl radicals in complexes with hydrogen and deuterium.

Format:

Book

Thesis/Dissertation

Author/Creator:

Todd, Michael Wingate.

Contributor:

Lester, Marsha I., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Chemistry, Physical and theoretical.

Analytical chemistry.

0486.

0494.

Penn dissertations--Chemistry.

Chemistry--Penn dissertations.

Local Subjects:

Penn dissertations--Chemistry.

Chemistry--Penn dissertations.

0486.

0494.

Physical Description:

266 pages

Contained In:

Dissertation Abstracts International 61-03B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

Characterizing reactive potential energy surfaces is a constant challenge in quantum chemistry. In this laboratory, a novel technique, which has general applicability, has been developed to investigate the entrance channel to the OH X2pi + H2X 1Sigmag+ → H2O + H reaction. The reactants have been stabilized in a weakly bound complex within a shallow attractive well in the entrance channel, making the H2-OH reactant pair amenable to spectroscopic investigation. Infrared and stimulated Raman experiments have been implemented to excite the OH and H2 intramolecular stretching modes, respectively, as well as intermolecular bending vibrations. The resultant spectra have enabled the bound states of o-H 2-OH and D2-OH to be characterized and compared with ab initio predictions. Additionally, vibrational activation initiates both reactive and inelastic scattering events, as it provides enough energy to surmount the barrier to reaction or, alternatively, to break the weak intermolecular bond. The lifetimes of the vibrationally excited states reveal the sum of the rates for reactive and inelastic scattering, while the OH (v = 1) product rotational distributions reflect the inelastic scattering dynamics between OH and H2/D2 under restricted initial orientation conditions.

Electronically excited OH A2Sigma + radicals are efficiently quenched in collisions with H2. Collisional deactivation can proceed by electronic relaxation to form ground state OH X2pi + H2 or by a reactive pathway that generates H2O + H. Reactive quenching of OH A2Sigma+ in collisions with H 2 has been characterized by H-atom Doppler spectroscopy and is found to be a significant decay channel.

Notes:

Thesis (Ph.D. in Chemistry) -- University of Pennsylvania, 2000.

Source: Dissertation Abstracts International, Volume: 61-03, Section: B, page: 1431.

Supervisor: Marsha I. Lester.

Local Notes:

School code: 0175.

ISBN:

9780599701953

Access Restriction:

Restricted for use by site license.