Stimulated Raman and electronic excitation of CH4–OH reactant complexes

Tsiouris, Maria; Wheeler, Martyn D.; Lester, Marsha I.

doi:10.1016/s0009-2614(99)00075-5

Cited by 19 publications

(36 citation statements)

References 27 publications

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“…For the diatomic hydrides, this is almost exclusively the work on the H 2 •OH complex, 10 although work has also commenced upon the CH 4 •OH complex. 11 Regarding NO-containing complexes, reports of electronic spectra of ''NO•N 2 ,'' 12 NO•CH 4 , 13,14 and NO•C 2 H 6 15 have been made. It should be noted at this point that the most detailed results on the ground X 2 ⌸ state ͑where the nomenclature implies that the complex involves interaction with NO in the X 2 ⌸ state͒ have come from microwave/radiofrequency and infrared experiments.…”

Section: Introductionmentioning

confidence: 99%

The Ã←X̃(1+1)REMPI spectrum and high-level ab initio calculations of the complex between NO and N2

Lozeille

Daire

Gamblin

et al. 2000

The Journal of Chemical Physics

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The results of two separate studies of the complex between NO and N 2 are reported. The (1 ϩ1) REMPI spectrum of the Ã ←X transition of the complex between NO and N 2 is presented of improved quality over that reported previously, and the appearance of the spectrum is discussed. The results of high-level ab initio calculations ͓RCCSD͑T͒/aug-cc-pVQZ//QCISD/6-311ϩG͑2d͔͒ on the X 2 ⌸ state are also reported. The indications are that the NO moiety is more freely rotating in the complex than is N 2 , and that a wide angular space is sampled in the zero-point energy level. The appearance of the REMPI spectrum suggests that the Ã 2 ⌺ ϩ state is ͑close to͒ linear, and RCCSD͑T͒//QCISD calculations on the Ã state, using Rydberg-function-augmented basis sets, suggest that the lowest energy linear isomer is the ON•N 2 linear orientation. It is clear, however, that the understanding of this complex, and its spectroscopy, is far from complete, and will be challenging.

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Section: Introductionmentioning

confidence: 99%

The Ã←X̃(1+1)REMPI spectrum and high-level ab initio calculations of the complex between NO and N2

Lozeille

Daire

Gamblin

et al. 2000

The Journal of Chemical Physics

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“…34 The experimental method used to produce CH 4 -OH complexes has been described in previous publications. 22,23 Briefly, OH radicals are produced in a pulsed supersonic expansion via the 193 nm photolysis of nitric acid in a 10% CH 4 /balance He gas mixture ͑150 psi͒ using an ArF excimer laser ͑Lambda Physik, EMG 101 MSC͒. The photolysis occurs within a quartz capillary tube attached to the faceplate of a pulsed solenoid valve.…”

Section: Methodsmentioning

confidence: 99%

“…22 Briefly, SRE of CH 4 -OH complexes is effected by the use of two visible laser pulses, conventionally denoted as pump and Stokes, both generated by a Nd:YAG pumped dye laser system. A portion of the second harmonic output of the Nd:YAG laser was used as the pump pulse and the Stokes dye laser was tuned such that the difference in frequency between the pump and Stokes lasers was in the vicinity of the 1 transition of CH 4 at 2916 cm Ϫ1 .…”

Section: Methodsmentioning

confidence: 99%

“…Preliminary results of stimulated Raman excitation of the 1 mode were presented in an earlier publication. 22 A previous study also examined vibrational activation of the OH fundamental and overtone stretches of CH 4 -OH, 23 which will be compared with the results of the present investigation.…”

Section: Introductionmentioning

confidence: 98%

“…19 In this laboratory, we have been pursuing a new approach to investigating the CH 4 ϩOH reaction based on stabilizing the reactants in a shallow attractive well in the entrance channel to reaction. 22,23 This procedure prepares the reactants in a weakly bound complex with a relatively con-strained geometry. Vibrational excitation of the CH 4 symmetric stretch ( 1 ), the CH 4 asymmetric stretch ( 3 ), or the OH stretch ( OH ) of CH 4 -OH via stimulated Raman or infrared excitation provides sufficient energy to surmount the activation barrier to reaction or, alternatively, to break the weak intermolecular bond.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Activation of the CH stretching vibrations in CH4–OH entrance channel complexes: Spectroscopy and dynamics

Tsiouris

Wheeler

Lester

2001

The Journal of Chemical Physics

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Articles you may be interested inMode-selective O-H stretching relaxation in a hydrogen bond studied by ultrafast vibrational spectroscopy J. Chem. Phys. 125, 074504 (2006); 10.1063/1.2219111 Comparing the dynamical effects of symmetric and antisymmetric stretch excitation of methane in the Cl + CH 4 reaction J. Chem. Phys. 120, 5096 (2004); 10.1063/1.1647533 OH vibrational activation and decay dynamics of CH 4 -OH entrance channel complexes Intermolecular interaction in the CH 3 + -He ionic complex revealed by ab initio calculations and infrared photodissociation spectroscopy J. Chem. Phys. 110, 9527 (1999); 10.1063/1.478917 Structures and the vibrational relaxations of size-selected benzonitrile-( H 2 O ) n=1-3 and -( CH 3 OH ) n=1-3 clusters studied by fluorescence detected Raman and infrared spectroscopiesThe vibrational spectroscopy and decay dynamics of CH 4 -OH reactant complexes have been studied in the CH 4 symmetric and antisymmetric stretching regions ( 1 and 3 ). The vibrational spectra have been obtained using both infrared and stimulated Raman excitation with ultraviolet probe laser-induced fluorescence detection. Stimulated Raman excitation of CH 4 -OH in the symmetric stretching region reveals two blended Q branch features at 2912.5 and 2911.8 cm Ϫ1 . An extremely weak infrared spectrum is also seen in the CH 4 symmetric stretching region, which is induced by the presence of the nearby OH partner. Infrared excitation in the asymmetric stretching region results in an intense, yet enormously broad spectrum centered at 3020 cm Ϫ1 that extends over 40 cm Ϫ1 . The appearance of the spectra in the 1 and 3 regions has been explained in terms of a model in which the CH 4 unit undergoes internal rotation within the CH 4 -OH complex. The 1 features are attributed to transitions involving two different nuclear spin states of CH 4 . In the 3 region, the CH 4 -OH complex can undergo a multitude of allowed transitions, each associated with a rovibrational transition of free methane, which give rise to the enormous span of the spectrum. The vibrational spectra also exhibit extensive homogeneous broadening ͑у1 cm Ϫ1 ͒ arising from the rapid decay of vibrationally activated CH 4 -OH complexes due to vibrational predissociation and possibly reaction. The OH fragments are produced with minimal rotational excitation, indicating that the dominant inelastic decay channel involves near-resonant vibrational energy transfer within the CH 4 unit from the initially prepared CH stretch to an overtone bend (2 4 ) state.

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Ab initio study of atmospheric reactions of the hydroxyl radical–water complex (OH–H2O) with saturated hydrocarbons (methane, ethane and propane)

Karakuş

Ozkan

2005

Journal of Molecular Structure: THEOCHEM

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Stimulated Raman and electronic excitation of CH4–OH reactant complexes

Cited by 19 publications

References 27 publications

The Ã←X̃(1+1)REMPI spectrum and high-level ab initio calculations of the complex between NO and N2

The Ã←X̃(1+1)REMPI spectrum and high-level ab initio calculations of the complex between NO and N2

Activation of the CH stretching vibrations in CH4–OH entrance channel complexes: Spectroscopy and dynamics

Ab initio study of atmospheric reactions of the hydroxyl radical–water complex (OH–H2O) with saturated hydrocarbons (methane, ethane and propane)

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