Vibration→Vibration Energy Transfer

Moore, C. Bradley

doi:10.1002/9780470143735.ch2

Cited by 159 publications

(5 citation statements)

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“…It is particularly remarkable that the kinetic curves in Figure , showing the growth and decay of the CIQCB signal, reach their maximum value within an IR−UV delay interval corresponding to z = 1 in the case of neat C 2 H 2 and to z tot = 5 with 1:10 C 2 H 2 /Ar mixtures. This implies that the corresponding transfer efficiencies are much higher than would be expected for simple thermal equilibration (e.g., by vibration-to-translation/rotation energy transfer). − As will be discussed in Section IV below, such kinetics are consistent with collision-induced intramolecular V−V energy transfer. Figures and have significant mechanistic implications, concerning the CIQCB bath kinetics (whether they are collision-induced and, if so, intramolecular or intermolecular), as discussed in Section IV below.…”

Section: Ir−uv Dr Spectra and Kinetics With Uv Probe At ∼299 Nmmentioning

confidence: 96%

“…Time-resolved optical double-resonance (DR) spectroscopy, using successive laser pulses for pumping and probing, is a well-established way to explore the energetics, energy-transfer dynamics, and reactivity of polyatomic molecules. In particular, collision-induced state-to-state energy transfer in the gas phase is of long-standing intrinsic interest, − with ongoing challenges presented by highly excited rovibrational manifolds (e.g., above ∼10 000 cm -1 ) of small polyatomic molecules with just a few atoms (e.g., 3−6). Such rovibrational manifolds are congested and relevant in other contexts such as chemical reaction dynamics − and intramolecular vibrational redistribution (IVR). ,− Moreover, intramolecular perturbations influence collision-induced energy-transfer efficiencies in small polyatomics, − contrasting with the more highly congested rovibrational manifolds in larger polyatomic molecules.…”

Section: Introductionmentioning

confidence: 99%

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Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

et al. 2006

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The 4nu(CH) rovibrational manifold around 12 700 cm(-1) in the electronic ground state, X, of acetylene (C2H2) is monitored by time-resolved infrared-ultraviolet double-resonance (IR-UV DR) spectroscopy. An IR laser pulse initially prepares rotational J states, associated with the "IR-bright" (nu1 + 3nu3) or (1 0 3 0 0)0 vibrational combination level, and subsequent collision-induced state-to-state energy transfer is probed by UV laser-induced fluorescence. Anharmonic, l-resonance, and Coriolis couplings affect the J states of interest, resulting in a congested rovibrational manifold that exhibits complex intramolecular dynamics. In preceding papers in this series, we have described three complementary forms of the IR-UV DR experiment (IR-scanned, UV-scanned, and kinetic) on collision-induced rovibrational satellites, comprising both regular even-DeltaJ features and unexpected odd-DeltaJ features. This paper examines an unusual collision-induced quasi-continuous background (CIQCB) effect that is apparently ubiquitous, accompanying regular even-DeltaJ rovibrational energy transfer and accounting for much of the observed collision-induced odd-DeltaJ satellite structure; certain IR-bright (1 0 3 0 0)0 rovibrational states (e.g., J = 12) are particularly prominent in this regard. We examine the mechanism of this CIQCB phenomenon in terms of a congested IR-dark rovibrational manifold that is populated by collisional transfer from the nearly isoenergetic IR-bright (1 0 3 0 0)0 submanifold.

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Section: Ir−uv Dr Spectra and Kinetics With Uv Probe At ∼299 Nmmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

et al. 2006

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“…Progress is now limited simply by the complexity resulting from the number of possible vibrational energy transfers (79). Study of the work on carbon dioxide or methane above or on methyl fluoride by George Flynn and his group illustrates how challenging it is to measure a full set of rate constants (80) for all possible energy transfers for a polyatomic gas or a mixture of polyatomics.…”

Section: Wwwannualreviewsorg • Energy Transfers and Chemical Reactimentioning

confidence: 99%

“…Nevertheless, we know a great deal about the dependence of rates on quantum-number changes, on the amount of vibrational energy to be transferred into translation and rotation, on the steepness of the repulsive intermolecular potential, on chemical-or hydrogen-bonding interactions, on long-range multipolar transition moments for nearly resonant V → V transfers, on the velocity of translation and of rotation relative to those of vibration, and so on. (79,81). One can estimate whether inverted populations may be created and maintained in a chemically reacting mixture or in an electrical discharge.…”

Section: Wwwannualreviewsorg • Energy Transfers and Chemical Reactimentioning

confidence: 99%

A Spectroscopist's View of Energy States, Energy Transfers, and Chemical Reactions

Moore

2007

Annu. Rev. Phys. Chem.

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This chapter describes a research career beginning at Berkeley in 1960, shortly after Sputnik and the invention of the laser. Following thesis work on vibrational spectroscopy and the chemical reactivity of small molecules, we studied vibrational energy transfers in my own lab. Collision-induced transfers among vibrations of a single molecule, from one molecule to another, and from vibration to rotation and translation were elucidated. My research group also studied the competition between vibrational relaxation and chemical reaction for potentially reactive collisions with one molecule vibrationally excited. Lasers were used to enrich isotopes by the excitation of a predissociative transition of a selected isotopomer. We also tested the hypotheses of transition-state theory for unimolecular reactions of ketene, formaldehyde, and formyl fluoride by (a) resolving individual molecular eigenstates above a dissociation threshold, (b) locating vibrational levels at the transition state, (c) observing quantum resonances in the barrier region for motion along a reaction coordinate, and (d) studying energy release to fragments. GETTING STARTEDI had the good fortune to grow up on a farm in eastern Pennsylvania, where hard work produced good crops, poultry, and livestock; where I could help my father take apart, repair, and reassemble farm equipment; and where I could manufacture and experiment with gun powder. In those days, parents could still give chemistry sets to their children, and the East Coast sky was often clear enough to observe shooting stars while lying flat on the bed of a hay wagon. This constituted my first spectroscopic observations of chemistry in action. My initial in-class chemistry lab was a study of sulfur combustion carried out by placing a fumigation candle in the ink well of my third-grade desk and lighting it on departure for recess. This early initiative was not encouraged on my return from the playground. One of Princeton Professor Hubert Alyea's renowned lectures on the marvels of chemistry at a nearby high school provided my first look at cryogenics as he exhaled through a mouth full of dry ice. By the time I finished a series of integrated courses in the physical sciences, a one-week visit by J. Robert Oppenheimer, and a challenging course in analytical/inorganic chemistry in high school (Phillips Exeter Academy in New Hampshire), I was well on my way to becoming a physical chemist. The launching of Sputnik during my first month of college (October 1957) at Harvard sharply increased federal funding for scientific research and greatly encouraged scientific career paths. That fall, the intensity of lab courses in physics and organic chemistry, a fourth-semester calculus course, and a humanities course quickly ended my aspiration to extend my high-school crew experience to intercollegiate rowing. A series of research projects in Paul D. Bartlett's personal lab at Harvard and summer jobs at Arthur D. Little and General Electric's corporate research lab deepened my interest and experi...

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“…Collision-induced state-to-state energy transfer in congested rovibrational energy manifolds of polyatomic molecules in the gas phase has long been of interest, both intrinsically − and in other contexts such as unimolecular reaction dynamics − and intramolecular vibrational redistribution. ,− It remains a challenge to characterize collision-induced energy transfer involving highly excited rovibrational states of small polyatomic molecules with just a few atoms (e.g., 3−6). Such investigations provide useful comparisons (and contrasts) with corresponding studies of the more highly congested rovibrational manifolds in larger polyatomic molecules. ,− This interface between the dynamics of large and small molecules is well-exemplified by the series of experiments by Flynn and co-workers on intermolecular rovibrational energy transfer between large donor molecules such as highly vibrationally excited pyrazine and a “bath” of small acceptor molecules such as CO 2 21 or CO …”

Section: Introductionmentioning

confidence: 99%

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene Viewed by IR−UV Double Resonance Spectroscopy. 2. Perturbed States withJ= 17 and 18

et al. 2005

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Collision-induced state-to-state molecular energy transfer between rovibrational states in the 12,700 cm(-1) 4nu(CH) manifold of the electronic ground state X of acetylene (C(2)H(2)) is monitored by time-resolved infrared-ultraviolet double resonance (IR-UV DR) spectroscopy. Rotational J-states associated with the (nu(1) + 3nu(3)) or (1 0 3 0 0)(0) vibrational combination level, initially prepared by an IR pulse, are probed at approximately 299, approximately 296, or approximately 323 nm with UV laser-induced fluorescence via the Alpha electronic state. The rovibrational J-states of interest belong to a congested manifold that is affected by anharmonic, l-resonance, and Coriolis couplings, yielding complex intramolecular dynamics. Consequently, collision-induced rovibrational satellites observed by IR-UV DR comprise not only regular even-DeltaJ features but also supposedly forbidden odd-DeltaJ features. A preceding paper (J. Phys. Chem. A 2003, 107, 10759) focused on low-J-value rovibrational levels of the 4nu(CH) manifold (particularly those with J = 0 and J = 1) whereas this paper examines locally perturbed states at higher values of J (particularly J = 17 and 18, which display anomalous doublet structure in IR-absorption spectra). Three complementary forms of IR-UV DR experiments (IR-scanned, UV-scanned, and kinetic) are used to address the extent to which intramolecular perturbations influence the efficiency of J-resolved collision-induced energy transfer with both even and odd DeltaJ.

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Vibration→Vibration Energy Transfer

Cited by 159 publications

References 139 publications

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

A Spectroscopist's View of Energy States, Energy Transfers, and Chemical Reactions

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene Viewed by IR−UV Double Resonance Spectroscopy. 2. Perturbed States withJ= 17 and 18

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Vibration→Vibration Energy Transfer

Cited by 159 publications

References 139 publications

Rovibrational Energy Transfer in the 4νCHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

Rovibrational Energy Transfer in the 4νCHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

A Spectroscopist's View of Energy States, Energy Transfers, and Chemical Reactions

Rovibrational Energy Transfer in the 4νCHManifold of Acetylene Viewed by IR−UV Double Resonance Spectroscopy. 2. Perturbed States withJ= 17 and 18

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Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects

Rovibrational Energy Transfer in the 4ν_CHManifold of Acetylene Viewed by IR−UV Double Resonance Spectroscopy. 2. Perturbed States withJ= 17 and 18