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Kay JJ, Steill JD, Kłos J, Paterson G, Costen ML, Strecker KE, McKendrick KG, Alexander MH, Chandler DW. Collisions of electronically excited molecules: differential cross-sections for rotationally inelastic scattering of NO(A2Σ+) with Ar and He. Mol Phys 2012. [DOI: 10.1080/00268976.2012.670283] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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McCaffery AJ, Marsh RJ. Competitive partitioning of rotational energy in gas ensemble equilibration. J Chem Phys 2012; 136:024307. [DOI: 10.1063/1.3675638] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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McCaffery AJ, Pritchard M, Turner JF, Marsh RJ. Equilibration of OH (v7; v9) in air-like gas ensembles. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.09.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Clegg SM, Parmenter CS. Inelastic scattering from glyoxal: collision kinematics rather than the interaction potential dominates rotational channel selection. J Chem Phys 2006; 125:133110. [PMID: 17029436 DOI: 10.1063/1.2336222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Relative cross sections have been obtained for the rotationally and rovibrationally inelastic scattering of S1 trans-glyoxal (CHO-CHO) in its zero point level with K' = 0 from the target gases H2, D2, and He. Emphasis is placed on using crossed molecular beam conditions that provide several choices of collision kinematics (center-of-mass collision energy, relative velocity, center-of-mass collision momentum) for each collision pair. The cross sections define the state-to-state competition among numerous rotational channels involving destination states with DeltaK' ranging from 1 to >15 for collisions with each target gas and under every kinematic condition. They also resolve a similar rotational competition among rovibrational channels where the torsion nu7' is collisionally excited. The cross section sets also allow the relative overall magnitudes of the two types of scattering to be compared. The primary motivation of these experiments concerns the rotationally inelastic scattering. Earlier studies with rare gases and fixed kinematics demonstrated that the distribution of rotational cross sections is remarkably similar from one collision pair to another. The new data show that the competition among rotational channels actually has a small but distinct dependence on kinematic conditions. Data analysis shows that the dependence is a systematic function of the available collision momentum and entirely unrelated to the identity of the target gases, including the heavier rare gases used in earlier studies. The competition among the rotational energy transfer channels and its kinematic heritage is discussed in the context of a classical hard ellipse model of linear momentum to angular momentum conversion much used with room temperature systems. When adapted to our beam conditions, the resulting account of the rotational scattering is accurate and provides insight into the collisional details.
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Affiliation(s)
- Samuel M Clegg
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
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Li Z, Korobkova E, Werner K, Shum L, Mullin AS. State-resolved collisional quenching of vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) by D35Cl(v = 0). J Chem Phys 2005; 123:174306. [PMID: 16375527 DOI: 10.1063/1.2098647] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Supercollision relaxation of highly vibrationally excited pyrazine (E(vib) = 37,900 cm(-1)) with D35Cl is investigated using high-resolution transient IR diode laser absorption spectroscopy at 4.4 microm. Highly excited pyrazine is prepared by pulsed UV excitation at 266 nm, followed by rapid radiationless decay to the ground electronic state. The rotational energy distribution of the scattered DCl (v = 0,J) molecules with J = 15-21 is characterized by T(rot) = 755+/-90 K. The relative translational energy increases as a function of rotational quantum number for DCl with T(rel) = 710+/-190 K for J = 15 and T(rel) = 1270+/-240 K for J = 21. The average change in recoil velocity correlates with the change in rotational angular momentum quantum number and highlights the role of angular momentum in energy gain partitioning. The integrated energy-transfer rate for appearance of DCl (v = 0,J = 15-21) is k(2)(int) = 7.1x10(-11) cm3 molecule(-1) s(-1), approximately one-eighth the Lennard-Jones collision rate. The results are compared to earlier energy gain measurements of CO2 and H2O.
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Affiliation(s)
- Ziman Li
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
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Duca MD. The effect of kinematic parameters on inelastic scattering of glyoxal. J Chem Phys 2004; 121:6750-8. [PMID: 15473731 DOI: 10.1063/1.1789471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The effect of kinematic parameters (relative velocity v(rel), relative momentum p(rel), and relative energy E(rel)) on the rotational and rovibrational inelastic scatterings of 0(0)K(0)S(1) trans-glyoxal has been investigated by colliding glyoxal seeded in He or Ar with target gases D2, He, or Ne at different scattering angles in crossed supersonic beams. The inelastic spectra for target gases He and D2 acquired with two different sets of kinematic parameters revealed no significant differences. This result shows that kinematic factors have the major influence in the inelastic scattering channel competition whereas the intermolecular potential energy surface plays only a secondary role. The well-defined exponential dependence of relative cross sections on exchanged angular momentum identifies angular momentum as the dominant kinematic factor in collision-induced rotationally and rovibrationally inelastic scatterings. This is supported by the behavior of the relative inelastic cross sections data in a "slope-p(rel)" representation. In this form, the data show a trend nearly independent of the target gas identity. Representations involving E(rel) and v(rel) show trends specific to the target gas.
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Affiliation(s)
- Mariana D Duca
- Laboratory of Physics, Department of Chemistry, University of Bucharest, Boulevard Regina Elisabeta 4-12, Bucharest 1, Romania.
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McCaffery AJ, Osborne MA, Marsh RJ, Lawrance WD, Waclawik ER. The role of angular momentum in collision-induced vibration–rotation relaxation in polyatomics. J Chem Phys 2004; 121:169-80. [PMID: 15260535 DOI: 10.1063/1.1758696] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vibrational relaxation of the 6(1) level of S(1)((1)B(2u)) benzene is analyzed using the angular momentum model of inelastic processes. Momentum-(rotational) angular momentum diagrams illustrate energetic and angular momentum constraints on the disposal of released energy and the effect of collision partner on resultant benzene rotational excitation. A kinematic "equivalent rotor" model is introduced that allows quantitative prediction of rotational distributions from inelastic collisions in polyatomic molecules. The method was tested by predicting K-state distributions in glyoxal-Ne as well as J-state distributions in rotationally inelastic acetylene-He collisions before being used to predict J and K distributions from vibrational relaxation of 6(1) benzene by H(2), D(2), and CH(4). Diagrammatic methods and calculations illustrate changes resulting from simultaneous collision partner excitation, a particularly effective mechanism in p-H(2) where some 70% of the available 6(1)-->0(0) energy may be disposed into 0-->2 rotation. These results support the explanation for branching ratios in 6(1)-->0(0) relaxation given by Waclawik and Lawrance and the absence of this pathway for monatomic partners. Collision-induced vibrational relaxation in molecules represents competition between the magnitude of the energy gap of a potential transition and the ability of the colliding species to generate the angular momentum (rotational and orbital) needed for the transition to proceed. Transition probability falls rapidly as DeltaJ increases and for a given molecule-collision partner pair will provide a limit to the gap that may be bridged. Energy constraints increase as collision partner mass increases, an effect that is amplified when J(i)>0. Large energy gaps are most effectively bridged using light collision partners. For efficient vibrational relaxation in polyatomics an additional requirement is that the molecular motion of the mode must be capable of generating molecular rotation on contact with the collision partner in order to meet the angular momentum requirements. We postulate that this may account for some of the striking propensities that characterize polyatomic energy transfer.
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Affiliation(s)
- Anthony J McCaffery
- Department of Chemistry, University of Sussex, Brighton BN19QJ, United Kingdom
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Waclawik ER, Lawrance WD. Rotational Changes Accompanying Vibrational Transfer in Low-Energy Collisions between Benzene and H 2, D 2, and CH 4. J Phys Chem A 2003. [DOI: 10.1021/jp035560+] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Eric R. Waclawik
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Warren D. Lawrance
- School of Chemistry, Physics and Earth Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
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Marsh RJ, McCaffery AJ, Osborne MA. Quantitative Calculation of Product Rovibrational Distributions from Atom−Diatom Exchange Reactions. J Phys Chem A 2003. [DOI: 10.1021/jp0305584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Richard J. Marsh
- Department of Chemistry, University of Sussex, Brighton BN19QJ, U.K
| | | | - Mark A. Osborne
- Department of Chemistry, University of Sussex, Brighton BN19QJ, U.K
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Payne MA, Milce AP, Frost MJ, Orr BJ. Rovibrational Energy Transfer in the 4νCH Manifold of Acetylene, Viewed by IR−UV Double Resonance Spectroscopy. 1. Foundation Studies at Low J. J Phys Chem A 2003. [DOI: 10.1021/jp035224t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark A. Payne
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
| | - Angela P. Milce
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
| | - Michael J. Frost
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
| | - Brian J. Orr
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
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Wilhelm R, Lindner J. Observation of collision induced state-to-state energy transfer in electronically and highly rotationally excited NH2. J Chem Phys 2001. [DOI: 10.1063/1.1359243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Clare S, Marks AJ, McCaffery AJ. Why Are Collision Induced Rotational Distributions Unresponsive to Kinematic Differences? J Phys Chem A 2000. [DOI: 10.1021/jp994392b] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Suzanne Clare
- School of Chemistry, Physics and Environmental Sciences, University of Sussex, Brighton BN19QJ, U.K
| | - Alison J. Marks
- School of Chemistry, Physics and Environmental Sciences, University of Sussex, Brighton BN19QJ, U.K
| | - Anthony J. McCaffery
- School of Chemistry, Physics and Environmental Sciences, University of Sussex, Brighton BN19QJ, U.K
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Truhins K, Marsh R, McCaffery AJ, Whiteley TWJ. A simple model for product rovibrational distributions in elementary chemical reactions. J Chem Phys 2000. [DOI: 10.1063/1.481098] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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