Rotationally resolved quenching and relaxation of CH(A2Δ,v=0,N) in the presence of CO

Meden, P.; Kind, Martin; Stuhl, F.

doi:10.1063/1.1436110

Cited by 7 publications

(14 citation statements)

References 39 publications

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“…More generally, our results confirm the conclusions reached in a number of previous studies 16,23,28,33,47,48 that only the collision partners CO and H 2 cause relatively rapid total removal of CH (B) and CH (A). It is conceivable that the respective k B0X , k A1X , and k A0X and rate constants contain contributions from quenching to the electronic ground state, X 2 Π, or even, in principle, the lower-lying a 4 Σ -state.…”

Section: Discussionsupporting

confidence: 93%

“…There has also been considerable related discussion of multipole models of attractive forces which attempt to explain the rotational level dependence of total quenching. 16,29,33,39,41,47,48,62 We believe this is the first time that the Parmenter-Seaver approach has been applied to a specific electronic channel for CH. An immediate practical implication of the apparent positive correlation is that it should provide a simple method for predicting the relative efficiencies of CH B T A coupling for other (unmeasured) partners, at least at a fixed temperature.…”

Section: Discussionmentioning

confidence: 98%

“…[39][40][41][42][43][44][45][46][47][48] VET has also been studied in the A and B states of CH. 40,41 The main focus of this work is collision-induced EET, specifically that between the A 2 ∆ and B 2 Σ -states of CH.…”

Section: Introductionmentioning

confidence: 99%

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Collision-Partner Dependence of Energy Transfer between the CH A²Δ and B²Σ^- States

2005

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We have investigated experimentally the collision-induced electronic energy transfer between the CH A(2)Delta and B(2)Sigma(-) states with the series of partners He, Ar, H(2), N(2), CO, and CO(2). Single rovibronic states of either of the near-degenerate levels A(2)Delta, v = 1, or B(2)Sigma(-), v = 0, were prepared by laser excitation. Collisional transfer processes were monitored by detecting dispersed, time-resolved fluorescence from the initial and product states. The microscopic rate constants for vibronically resolved transfer between the A(2)Delta and B(2)Sigma(-) states, vibrational relaxation within the A state, and total removal to unobserved final products were determined for each partner. In line with previous work, we find that only CO and H(2) are efficient at total removal of CH A(2)Delta and B(2)Sigma(-), most probably through chemical reaction. CO(2) is notably effective at A(2)Delta state vibrational relaxation, possibly through resonant vibrational energy transfer. All the partners cause transfer between CH A(2)Delta and B(2)Sigma(-). An important new observation is that their efficiencies are well correlated with the strength of long-range attractive forces, as revealed through a positive correlation of the Parmenter-Seaver type. The vibronic branching to A(2)Delta, v = 0 and 1 from B(2)Sigma(-), v = 0 is found to be significantly collision-partner-dependent and not well predicted by energy gap scaling laws. We do not find any enhanced effectiveness in B(2)Sigma(-) to A(2)Delta coupling for those partners which form strongly bound intermediates, suggesting that this specific electronic channel is controlled by different regions of the potential energy surfaces.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 98%

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Collision-Partner Dependence of Energy Transfer between the CH A²Δ and B²Σ^- States

2005

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“…[1][2][3][4][5][6][7][8] In fact, recent Feature Articles in The Journal of Physical Chemistry A have reported 9,10 many of the challenges in designing experiments for the measurements of state-to-state cross sections of ion-molecule collisions. [1][2][3][4][5][6][7][8] In fact, recent Feature Articles in The Journal of Physical Chemistry A have reported 9,10 many of the challenges in designing experiments for the measurements of state-to-state cross sections of ion-molecule collisions.…”

Section: Introductionmentioning

confidence: 99%

Global potential energy surfaces for the Al+(1S)+H2 system

Salazar

2004

The Journal of Chemical Physics

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Global, three-dimensional multireference ab initio potential energy surfaces have been calculated for the AlH2+ system for the two lowest energy singlet states and the lowest energy triplet state. These surfaces were calculated using the multireference configuration interaction level of theory with a large basis set. The accuracy of the surfaces were checked against available experimental data and previous theoretical investigations. The areas of surface crossings between the ground state singlet surface and the lowest energy triplet surface and the first excited singlet surface have been thoroughly investigated in all three dimensions and found to give rise to two regions of surface crossings--an "early" crossing (reduced H2 distance) and a "late" crossing (enlarged H2 distance). It is anticipated that both of these crossings will be important in modeling the dynamics of the system. Each of the global potential energy surfaces were fit by interpolation methodology to obtain analytic representations of the surfaces. A representative classical simulation on the ground state singlet surface was performed and discussed.

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“…[23][24][25][26][27][28][29][30][31] Although less well studied than OH, NH provides a further basis for useful comparison. [32][33][34][35][36] We will be concerned with RET in the lowest lying excited doublet state, CH A 2 D. In addition to work directly in flames, 3,4,37,38 rotationally inelastic collisions of both this state [39][40][41][42][43][44] and the nearby B 2 S À state 41,45,46 have been studied with selected partners in more controlled environments. Kind and Stuhl 46 have recently presented a state-to-state study of RET of CH B 2 S À , v ¼ 0, N, F i using Ar as the collision partner.…”

Section: Introductionmentioning

confidence: 99%

Rotational energy transfer in collisions of CH A²Δ, v = 0 with Ar, N₂and CO₂

Crichton

Murray

McKendrick

2002

Phys. Chem. Chem. Phys.

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Rotational energy transfer (RET) in collisions of CH A 2 D, v ¼ 0 with Ar, N 2 and CO 2 has been investigated experimentally. Laser excitation was used to prepare selected initial levels N ¼ 2,3,5 (all colliders), 8 (Ar and CO 2 ) and 14 (Ar only). Additional fine-structure state selection was achieved for the lower levels, and L-doublet selection for the higher levels. Total and state-to-state RET rate constants were extracted from time-resolved dispersed fluorescence spectra. Partial fine-structure-state resolution was possible for N 0 p 4, and L-doublet resolution for the highest levels. For Ar, good absolute agreement was found with previous state-selective experimental work and ab initio theoretical predictions. RET is substantially more efficient for N 2 and CO 2 , for which the first reliable absolute rate constants are provided. A change of fine-structure state with DN ¼ 0 is the most probable single state-to-state channel at low N for all three partners. Partial conservation of the finestructure label during DN 6 ¼ 0 collisions, previously observed for Ar, was found to extend to the other partners. The relative DN propensities are similar for all three partners. This is consistent with a simple impulsive model of the collision dynamics, in which energy constraints dominate because of the large rotational energy spacing characteristic of hydrides. This model does not, however, provide a straightforward explanation for the substantial differences in RET efficiency for Ar, N 2 and CO 2 .

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Rotationally resolved quenching and relaxation of CH(A2Δ,v=0,N) in the presence of CO

Cited by 7 publications

References 39 publications

Collision-Partner Dependence of Energy Transfer between the CH A²Δ and B²Σ^- States

Collision-Partner Dependence of Energy Transfer between the CH A²Δ and B²Σ^- States

Global potential energy surfaces for the Al+(1S)+H2 system

Rotational energy transfer in collisions of CH A²Δ, v = 0 with Ar, N₂and CO₂

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Rotationally resolved quenching and relaxation of CH(A2Δ,v=0,N) in the presence of CO

Cited by 7 publications

References 39 publications

Collision-Partner Dependence of Energy Transfer between the CH A2Δ and B2Σ- States

Collision-Partner Dependence of Energy Transfer between the CH A2Δ and B2Σ- States

Global potential energy surfaces for the Al+(1S)+H2 system

Rotational energy transfer in collisions of CH A2Δ, v = 0 with Ar, N2and CO2

Contact Info

Product

Resources

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Collision-Partner Dependence of Energy Transfer between the CH A²Δ and B²Σ^- States

Collision-Partner Dependence of Energy Transfer between the CH A²Δ and B²Σ^- States

Rotational energy transfer in collisions of CH A²Δ, v = 0 with Ar, N₂and CO₂