Theoretical studies of collisional energy transfer in highly excited molecules: temperature and potential surface dependence of relaxation in helium, neon, argon + carbon disulfide

Bruehl, Margaret; Schatz, George C.

doi:10.1021/j100337a013

Cited by 82 publications

(60 citation statements)

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“…4 This is consistent with numerous works which concluded that CET depends mainly on the repulsive part of the intermolecular potential and that, in general, a harder repulsive part results in larger energy transfers (see for example references 23,24,46 ).…”

Section: E Considerations Of Qualitative Versus Quantitative Predictsupporting

confidence: 89%

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Quasiclassical trajectory calculations of collisional energy transfer in propane systems: Multiple direct-encounter hard-sphere model

Linhananta

Lim

2002

Phys. Chem. Chem. Phys.

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Quasiclassical trajectory calculations of collisional energy transfer from highly vibrationally excited propane + rare gas systems are reported. This work extends our hard-sphere model K.F. Lim, Phys. Chem. Chem. Phys., 2000, 2, 1385) to examine the variation of the internal energy during collisions with a rare bath gas. This was accomplished by recording the vibrational and rotational energy of propane after each atom-atom encounter during trajectory simulations of propane + rare gas systems. This provides detailed information of the energy flow during a collision. It was found that collisions with small number of encounters transfer energy efficiently, whereas those with many encounters do not. Detailed analyses reveal that the former collisions arise from trajectories with high initial impact parameter, whereas the latter has small initial impact parameter. The reason behind this is the dependence of collision energy transfer (CET) of large polyatomic molecules on its shape. This is connected to the well-known role of rotational energy transfer (RET) as a gateway for CET.

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Section: E Considerations Of Qualitative Versus Quantitative Predictsupporting

confidence: 89%

“…Previous trajectory studies by our group and others have found that there is a strong correlation between the steepness of the repulsive interaction and the predicted CET, 16,23,24,28,46 implying that the present model would overestimate CET, but provide good qualitative trends for CET.…”

Section: Discussionmentioning

confidence: 56%

Quasiclassical trajectory calculations of collisional energy transfer in propane systems: Multiple direct-encounter hard-sphere model

Linhananta

Lim

2002

Phys. Chem. Chem. Phys.

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“…So, in view of these and similar observations made by Bruehl et al 29 and Hippler et al, 30 the global DMBE potential energy surface, which employs the realistic extended Hartree-Fock approximate correlation energy 26,31,32 (EHFACE2U) model, should provide a reliable representation of the potential energy both in the repulsive wall and long-range regions.…”

Section: Introductionmentioning

confidence: 69%

Six-Dimensional Energy-Switching Potential Energy Surface for HeHCN

Ansari

Varandas

2002

J. Phys. Chem. A

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A single-valued six-dimensional (6D) potential energy surface is determined for HeHCN by using the energy switching (ES) method, which utilizes a global double many-body expansion (DMBE) as well as a Legendre polynomial expansion for different energy regimes. The ES potential has a linear van der Waals well of 29.5 cm -1 which is about 4 cm -1 lower than that reported by Drucker et al. [J. Phys. Chem. 1995, 99, 2646 but agrees with one obtained by Atkins and Hutson [ J. Chem. Phys. 1996, 105, 440]. The effect of stretch of CN as well as CH bonds has also been investigated. With stretch, both the DMBE and ES schemes yield slightly deeper wells and steeper repulsion walls in the high energy region. Microwave transitions calculated at 15.9 and 31.3 GHz agree well with experiment and may be assigned to J ) 1 r 0 and J ) 2 r 1, respectively. This frequency is found to decrease with stretch. Finally, this ES potential energy surface has been compared with that of ArHCN reported by one of us [Chem. Phys. Lett. 1998, 297, 458]. Here, the question of transferability of the parameter which scales the Hatree-Fock energy in the rare gas-X (X ) H, C, and N) interaction from ArHCN to HeHCN has also been investigated. The transferability seems to work as it nicely brings out the position of the potential well and the rovibrational levels. The microwave transition, from the ground state (j ) 0, L ) 0, J ) 0) to state (1, 0, 1), found at 98.61 GHz in HeHCN can be compared with one found at about 162.48 GHz in ArHCN, in close agreement with experiment.

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“…These calculations can yield detailed information on the collisional energy transfer processes [18,[44][45][46][47][48][49][50][51][52][53][54], but their accuracy can be limited by the quality of the potential energy surfaces. Examples of recent studies include the collisional energy transfer calculations of Barker et al, that examined the degree of excitation and de-excitation of polyatomics in collisions with Ar [55], the collisional stabilization calculations of Babikov and co-workers [56], and the allyl + Ar trajectory studies of Conte et al [57,58] The accuracy of trajectory-based collisional energy transfer calculations can be inferred by comparing predicted lowpressure-limit and pressure-dependent rate coefficients--which are sensitive to collisional energy transfer--with available experimental results [59][60][61][62].…”

Section: Introductionmentioning

confidence: 99%

Determination of the collisional energy transfer distribution responsible for the collision-induced dissociation of NO2 with Ar

Steill

Jasper

Chandler

2015

Chemical Physics Letters

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a b s t r a c tCollisional energy transfer is an essential aspect of chemical reactivity and maintenance of thermal equilibrium. Here we report the shape (energy-dependence) of the collisional energy transfer probability function for collisions of vibrationally excited NO 2 entrained in a molecular beam and photoexcited to within 40 cm −1 of its dissociation threshold. The internally excited molecules undergo collisions with Ar atoms in a crossed beam apparatus. Dissociative collisions rapidly produce the NO(J) fragment, which is observed by velocity-mapped ion imaging and REMPI techniques. The measured collisional energy transfer function is obtained via energy conservation and is compared with the results of classical trajectory calculations. Good agreement between the theory and experiment is found for collisions that transfer small amounts of energy, but the theory predicts a higher likelihood of energetic collisions than is observed experimentally. We explore possible explanations for this discrepancy in the dynamics of the collision excitation process.Published by Elsevier B.V.

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Theoretical studies of collisional energy transfer in highly excited molecules: temperature and potential surface dependence of relaxation in helium, neon, argon + carbon disulfide

Cited by 82 publications

References 0 publications

Quasiclassical trajectory calculations of collisional energy transfer in propane systems: Multiple direct-encounter hard-sphere model

Quasiclassical trajectory calculations of collisional energy transfer in propane systems: Multiple direct-encounter hard-sphere model

Six-Dimensional Energy-Switching Potential Energy Surface for HeHCN

Determination of the collisional energy transfer distribution responsible for the collision-induced dissociation of NO2 with Ar

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