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Title: Temperature dependence of the photodissociation of CO 2 from high vibrational levels: 205-230 nm imaging studies of CO(X 1 Σ + ) and O( 3 P, 1 D) products

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [1]
  1. Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1361815
Grant/Contract Number:
FG02-05ER15629
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 147; Journal Issue: 1; Related Information: CHORUS Timestamp: 2018-02-15 00:47:17; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Sutradhar, S., Samanta, B. R., Samanta, A. K., and Reisler, H.. Temperature dependence of the photodissociation of CO 2 from high vibrational levels: 205-230 nm imaging studies of CO(X 1 Σ + ) and O( 3 P, 1 D) products. United States: N. p., 2017. Web. doi:10.1063/1.4979952.
Sutradhar, S., Samanta, B. R., Samanta, A. K., & Reisler, H.. Temperature dependence of the photodissociation of CO 2 from high vibrational levels: 205-230 nm imaging studies of CO(X 1 Σ + ) and O( 3 P, 1 D) products. United States. doi:10.1063/1.4979952.
Sutradhar, S., Samanta, B. R., Samanta, A. K., and Reisler, H.. 2017. "Temperature dependence of the photodissociation of CO 2 from high vibrational levels: 205-230 nm imaging studies of CO(X 1 Σ + ) and O( 3 P, 1 D) products". United States. doi:10.1063/1.4979952.
@article{osti_1361815,
title = {Temperature dependence of the photodissociation of CO 2 from high vibrational levels: 205-230 nm imaging studies of CO(X 1 Σ + ) and O( 3 P, 1 D) products},
author = {Sutradhar, S. and Samanta, B. R. and Samanta, A. K. and Reisler, H.},
abstractNote = {},
doi = {10.1063/1.4979952},
journal = {Journal of Chemical Physics},
number = 1,
volume = 147,
place = {United States},
year = 2017,
month = 7
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on April 20, 2018
Publisher's Accepted Manuscript

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  • The photodissociation of jet-cooled CF{sub 3}I into CF{sub 3{sup +}}I({sup 2}P{sub 3/2}) and CF{sub 3{sup +}}I*({sup 2}P{sub 1/2}) has been investigated between 304 and 277 nm by using velocity map ion imaging. The two-dimensional images provide detailed information on the partition of available energy into kinetic and internal energy of the photofragments. Vibrational structure with spacing of 695{+-}100cm{sup -1} is resolved in both I and I* images, indicating excitation of the umbrella mode {nu}{sub 2} of the CF{sub 3} photofragment. The fragment recoil anisotropies {beta}(I) and {beta}(I*) are determined as a function of the excitation wavelength and their variations aremore » interpreted in terms of the crossing between the {sup 3}Q{sub 0} and {sup 1}Q{sub 1} dissociative electronic states. The high-resolution images allow the determination of the variation of the anisotropy parameter {beta} as a function of the vibrational level of CF{sub 3} fragment, and provide a complementary method for the determination of the C-I bond energy. The vibrational dependence of the anisotropy values is discussed in terms of final-state interactions between the CF{sub 3} umbrella motion and the C-I dissociation coordinate, as discussed previously by Henning et al. [J. Chem. Phys. 84, 544 (1986)].« less
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  • UV excitation of jet-cooled CH{sub 2}OO X{sup 1}A′ to the excited B{sup 1}A′ electronic states results in dissociation to two spin-allowed product channels: H{sub 2}CO X{sup 1}A{sub 1} + O {sup 1}D and H{sub 2}CO a{sup 3}A″ + O {sup 3}P. In this study, the higher energy H{sub 2}CO a{sup 3}A″ + O {sup 3}P channel is characterized by velocity map imaging and UV action spectroscopy, in both cases utilizing 2 + 1 resonance enhanced multiphoton ionization detection of O {sup 3}P products, which complements a prior experimental study on the lower energy H{sub 2}CO X{sup 1}A{sub 1} + Omore » {sup 1}D channel [Lehman et al., J. Chem. Phys. 139, 141103 (2013)]. Anisotropic angular distributions indicative of rapid dissociation are obtained at 330 and 350 nm, along with broad and unstructured total kinetic energy distributions that provide insight into the internal excitation of the H{sub 2}CO a{sup 3}A″ co-fragment. A harmonic normal mode analysis points to significant vibrational excitation of the CH{sub 2} wag and C–O stretch modes of the H{sub 2}CO a{sup 3}A″ fragment upon dissociation. At each UV wavelength, the termination of the kinetic energy distribution reveals the energetic threshold for the H{sub 2}CO a{sup 3}A″ + O {sup 3}P product channel of ca. 76 kcal mol{sup −1} (378 nm) and also establishes the dissociation energy from CH{sub 2}OO X{sup 1}A′ to H{sub 2}CO X{sup 1}A{sub 1} + O{sup 1}D products of D{sub 0} ≤ 49.0 ± 0.3 kcal mol{sup −1}, which is in accord with prior theoretical studies. The threshold for the H{sub 2}CO a{sup 3}A″ + O {sup 3}P channel is also evident as a more rapid falloff on the long wavelength side of the O {sup 3}P action spectrum as compared to the previously reported UV absorption spectrum for jet-cooled CH{sub 2}OO [Beames et al., J. Am. Chem. Soc. 134, 20045 (2012)]. Modeling suggests that the O {sup 3}P yield increases uniformly from 378 to 300 nm.« less
  • H atoms produced in Lyman {alpha} photolysis of ethane, propane, and ethylene have been studied using velocity map imaging techniques. Two types of H atoms are identified, one formed along with an alkyl radical in the Rydberg state and the other by the subsequent decomposition of this Rydberg radical. {copyright} {ital 1998 American Institute of Physics.}
  • The temperature dependence of homogeneous and inhomogeneous vibrational linewidth broadening is reported for the symmetric CH/sub 3/-stretching vibration in acetonitrile over its entire liquid range at P = 1 atm. A selective excite-and-probe vibrational dephasing experiment based on transient stimulated Raman scattering in high laser depletion is used to measure the homogeneous dephasing times T/sub 2/. The separation of homogeneous and inhomogeneous broadening processes is accomplished using the combined results of isotropic spontaneous Raman studies and selective picosecond vibrational dephasing experiments. As a function of temperature, the relative contributions of homogeneous and inhomogeneous broadening are shown to change significantly inmore » opposing directions. Agreement between experiment and theory supports previous suggestions that homogeneous broadening is caused by rapidly varying processes which affect the vibration via short range repulsive forces. The results also suggest that inhomogeneous broadening is caused by slowly varying local density sites which interact with the vibration through long range attractive forces.« less