Vibrational energy transfer from four levels below 410 cm−1 in <i>S</i>1 <i>p</i>-difluorobenzene. I. A strong collision partner dependence in state-to-state transfer by monatomics

Mudjijono,; Lawrance, Warren D.

doi:10.1063/1.471487

Cited by 9 publications

(17 citation statements)

References 31 publications

(79 reference statements)

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“…Although most of these experiments have been done in a bulb 'thermal collision' arrangement, a few have utilized seeding the molecule in a molecular beam of the collider gas to precisely define the relative collision energy and initial state distributions of the collision partners [13,14]. Very few studies have been performed on a crossed molecular beam arrangement, such as the studies on glyoxal and I 2 by Parmenter and co-workers [15,16].…”

Section: Introductionmentioning

confidence: 98%

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A²Σ⁺) with Ar and He

et al. 2012

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The paper reports experimental measurements and theoretical calculations of rotational-state-resolved differential scattering cross-sections (DCS) for collisions between electronically excited NO(A 2 AE þ ) molecules and rare gas atoms. The experimental NO(A 2 AE þ ) þ Ar and NO(A 2 AE þ ) þ He state-resolved product scattering distributions are determined using velocity-mapped ion imaging. The ion images are analysed to determine the state-resolved DCS, which are compared with new theoretical DCS calculated using quantum scattering methods on ab initio electronic potential energy surfaces. Both collision systems are imaged simultaneously; this constraint on the collision energies of the two systems aids the comparison to theory. The experimental and calculated DCS agree well for the NO(A 2 AE þ )/He system. For the NO(A 2 AE þ )/Ar scattering system, the experiments do not recover the degree of forward-scattering theoretically predicted and significant differences in the positions of the observed and predicted rotational rainbow features are apparent at large scattering angles, particularly for the most rotationally inelastic collision channels investigated: DN ¼ 12,14.

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Section: Introductionmentioning

confidence: 98%

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A²Σ⁺) with Ar and He

et al. 2012

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“…In such circumstances the molecular density of states is too high to allow the paths for energy transfer to be elucidated. Recently, however, collision-induced vibrational energy transfer ͑VET͒ has been studied from four very low energy vibrational states in electronically excited (S 1 )pdifluorobenzene ͑pDFB͒ in supersonic free jet expansions of He, Ne, Ar, and Kr at 30-40 K. 1 The very small number of vibrational states accessible in these experiments has enabled the state-to-state pathways for vibrational energy flow to be assigned with little ambiguity following excitation of the 30 2 , 8 2 , 27 1 , and 6 1 states. Here we use the notation m n to indicate n quanta excitation of vibrational state m with 0 0 denoting the vibrational ground state.…”

Section: Introductionmentioning

confidence: 99%

“…1 Specifically, the probability of multiple quanta transitions increases as the bath gas changes from He to Kr. A further comparison with room temperature results 5 indicates that multiple quanta transitions also increase as the temperature is lowered.…”

Section: Introductionmentioning

confidence: 99%

“…The collision partner dependence of the VET process is therefore postulated as due to the influence of the attractive part of the intermolecular potential surface combined with velocity effects: the slower the incoming velocity the more time is available for the intermolecular potential to exert its influence. 1,6 In this paper we examine theoretical models for collision-induced VET in pDFB. Both quasiclassical trajectory calculations ͑QCT͒ and quantum vibrational closecoupling rotational infinite order sudden approximation calculations ͑VCC-IOS͒ 7,8 have been undertaken with the aim of comparing the approximations used in the two methods and understanding the experimental results.…”

Section: Introductionmentioning

confidence: 99%

“…1 Classical results have been calculated for the range of experimentally used colliders but for only the initial excitation of 30 2 and 8 2 . Quantum results, however, have been calculated for all four initially excited states but for only the He and, in some cases, the Ar collision partner.…”

Section: Introductionmentioning

confidence: 99%

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Classical and approximate quantum investigations of vibrational energy transfer in S1 p-difluorobenzene

Jordan

Clary

1997

The Journal of Chemical Physics

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Photoacoustic measurements of the vibrational relaxation of the selectively excited ozone (ν 3 ) molecule in pure ozone and its binary mixtures with O 2 ,N 2 , and noble gases A simple model potential energy surface is constructed and used in both quasiclassical trajectory calculations and quantum vibrational close-coupling, infinite order sudden approximation calculations of collision-induced vibrational energy transfer from four vibrational states of S 1 p-difluorobenzene. Classical and quantum state-to-state cross sections are compared for excitation of the two lowest energy vibrational states and collision with He or Ar. Qualitatively, the same trends are seen in both sets of results. Classical cross sections, however, are significantly larger at very low collision energies as a consequence of the binning procedures used to determine classical final states and, in the case of the Ar collider, as a result of the possible breakdown of the sudden approximation. Rotational excitation of the p-difluorobenzene molecule is also investigated and found to have only small effects on the dominant energy transfer channels. The theoretical results are compared with recent experimental results of Mudjijono and Lawrance ͓J. Chem. Phys. 104, 7444 ͑1996͔͒. The classical results, for the He, Ne, Ar, and Kr collision partners, show good agreement with experiment, reproducing the major energy transfer channels and the experimental collision partner dependence. Quantum results agree well with experiment for the He collider and are also used to assign experimentally ambiguous product states and to investigate vibrational energy transfer channels that are not experimentally observable. The propensity toward the transfer of multiple quanta of vibrational energy is analyzed and, in general, found to increase with the intermolecular well depth and with the mass of the collision partner. The He collision partner, however, behaves anomalously.

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Relaxation of the 6 Vibrational Level in ¹B₂_u Benzene by Polyatomic Colliders at Ultralow Temperatures

Waclawik

Lawrance

2003

J. Phys. Chem. A

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Vibrational energy transfer from the 61 level of S1 (1B2u) benzene has been studied at low collision energies in supersonic free jet expansions with 11 polyatomic collision partners. Each of the collision partners has available low lying vibrational levels so that relaxation can proceed via transfer of vibration in benzene to vibration in the collision partner (V → V transfer). Transfer to the 00 level of benzene is significant with each of these partners. From (a) comparisons with the behavior of the monatomic, diatomic, and small polyatomic partners studied previously and (b) previous results at room temperature [C. S. Parmenter, C. S.; Tang, K. Y. Chem. Phys. 1978, 27, 127], it is deduced that V → V transfer is responsible for the dominance of the 61 → 00 pathway. It is observed that the branching ratios for transfer to 00 are consistently largest for straight chain partners. The rotational contours of collisionally populated levels are fairly broad, revealing that significant rotational excitation accompanies vibrational relaxation. Boltzmann distribution fits to the rotational contours for 00 give temperatures that are on average slightly lower than those found for small polyatomics. The observation that a reasonable amount of energy is transferred into benzene rotation suggests that it is the low-frequency modes of the collision partner that are excited. Resonant or near resonant transfer appears to be inefficient. V → V and V → R transfer both appear to be operating in relaxation of 61 benzene yet are absent in relaxation from the related case of 61 p-difluorobenzene [Mudjijono; Lawrance, W. D. J. Chem. Phys. 1996, 105, 9874]. It is suggested that this difference arises because of a reduced efficiency for V → T transfer in the benzene case due to the 112 cm-1 higher frequency of ν6 in this molecule.

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Vibrational energy transfer from four levels below 410 cm−1 in S1 p-difluorobenzene. I. A strong collision partner dependence in state-to-state transfer by monatomics

Cited by 9 publications

References 31 publications

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A²Σ⁺) with Ar and He

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A²Σ⁺) with Ar and He

Classical and approximate quantum investigations of vibrational energy transfer in S1 p-difluorobenzene

Relaxation of the 6 Vibrational Level in ¹B₂_u Benzene by Polyatomic Colliders at Ultralow Temperatures

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Vibrational energy transfer from four levels below 410 cm−1 in S1 p-difluorobenzene. I. A strong collision partner dependence in state-to-state transfer by monatomics

Cited by 9 publications

References 31 publications

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A2Σ+) with Ar and He

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A2Σ+) with Ar and He

Classical and approximate quantum investigations of vibrational energy transfer in S1 p-difluorobenzene

Relaxation of the 6 Vibrational Level in 1B2u Benzene by Polyatomic Colliders at Ultralow Temperatures

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Product

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Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A²Σ⁺) with Ar and He

Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A²Σ⁺) with Ar and He

Relaxation of the 6 Vibrational Level in ¹B₂_u Benzene by Polyatomic Colliders at Ultralow Temperatures