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Journal of Physical Chemistry B
Volumn 112, Issue 2, 2008, Pages 369-377
Anomalously slow solvent structural relaxation accompanying high-energy rotational relaxation
Author keywords

[No Author keywords available]
Indexed keywords

COUPLINGS; FRICTION; NONLINEAR SYSTEMS; RANDOM PROCESSES; STRUCTURAL RELAXATION;
EID: 38749086841     PISSN: 15206106     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp075664a     Document Type: Article
Times cited : (6)
References (55)
  • 16
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    • The term linear response has been given a wide range of meanings in the solute-energy-relaxation literature. See ref 11 and Geissler, P. L, Chander, D. J. Chem. Phys. 2000, 113, 9759
    • The term "linear response" has been given a wide range of meanings in the solute-energy-relaxation literature. See ref 11 and Geissler, P. L.; Chander, D. J. Chem. Phys. 2000, 113, 9759.
  • 17
    • 34249983597 scopus 로고    scopus 로고
    • As we have emphasized in ref 11, the linear response failures relevant here are not the fairly routine cases that automatically occur when the equilibrium dynamics around a solute excited state differs from that around a ground-state solute. The cases interesting in our context are those that have the additional attribute of slow solvent dynamics induced by the solute excitation
    • Laird, B. B.; Thompson, W. H. J. Chem. Phys. 2007, 126, 211104. As we have emphasized in ref 11, the linear response failures relevant here are not the fairly routine cases that automatically occur when the equilibrium dynamics around a solute excited state differs from that around a ground-state solute. The cases interesting in our context are those that have the additional attribute of slow solvent dynamics induced by the solute excitation.
    • (2007) J. Chem. Phys , vol.126 , pp. 211104
    • Laird, B.B.1    Thompson, W.H.2
  • 29
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    • The choices for the initial solute rotational energies and solvent conditions used in this study were motivated by those employed in the ultrafast experiments described in ref 10 but were not attempts to mimic the experiments. In particular, our observation that liquid-state Ar seemed to cause the same kinds of relaxation behavior as that seen in experiment suggested that we concentrate our efforts in the simpler solvent. The actual experiments looked at CN rotors generated photochemically in ambient-temperature liquid water and alcohol solutions. Our simulated energetics, however, are more faithful to the experimental conditions. The rotationally hot channel for the actual photoreaction generated CNs with a broad range of rotational states centered near J, 40 corresponding to an average rotational energy of about 3000 cm -1, close to the largest initial rotational energies we study here, For a more detailed description of the connections with the experiments, as well as
    • -1, close to the largest initial rotational energies we study here). For a more detailed description of the connections with the experiments, as well as for other calculational details, see Tao, G. Ph.D. Thesis; Brown University: Providence, RI, 2007 and the on-line supplementary material for ref 10: (www.sciencemag.org/cgi/content/full/311/5769/1907/DC1).
  • 30
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    • Abramowitz, M, Stegun, I. A, Eds, Dover: New York
    • Handbook of Mathematical Functions; Abramowitz, M.; Stegun, I. A., Eds.; Dover: New York, 1972; pp 896, 897.
    • (1972) Handbook of Mathematical Functions
  • 31
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    • Although the phenomena we are trying to describe are entirely classical, it is convenient (and probably numerical equivalent in our applications) to use a quantum mechanical master equation that looks at transitions between discrete quantized rotational energy levels. Among its other virtues, this approach makes it straightforward to capture the microscopically correct kinematics of rotational energy transfer
    • Although the phenomena we are trying to describe are entirely classical, it is convenient (and probably numerical equivalent in our applications) to use a quantum mechanical master equation that looks at transitions between discrete quantized rotational energy levels. Among its other virtues, this approach makes it straightforward to capture the microscopically correct kinematics of rotational energy transfer.
  • 32
    • 84906368787 scopus 로고    scopus 로고
    • Had we assumed that the leading symmetry was that of a homonuclear solute, which is nearly the case for our system see ref 11, it is unlikely that there would have been any qualitative effect on the overall dynamics predicted by the master-equation
    • Had we assumed that the leading symmetry was that of a homonuclear solute, which is nearly the case for our system (see ref 11), it is unlikely that there would have been any qualitative effect on the overall dynamics predicted by the master-equation.
  • 33
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    • Prentice Hall: Upper Saddle River, NJ
    • McHale, J. L. Molecular Spectroscopy; Prentice Hall: Upper Saddle River, NJ, 1999; pp 228, 229.
    • (1999) Molecular Spectroscopy
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  • 34
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    • 2 or for solvents such as superfluid helium, rotational behavior in liquids is usually too dissimilar to its gas-phase counterpart for this kind of approach to provide an accurate portrait of the solvent-density-of-states effects.
    • 2 or for solvents such as superfluid helium, rotational behavior in liquids is usually too dissimilar to its gas-phase counterpart for this kind of approach to provide an accurate portrait of the solvent-density-of-states effects.
  • 37
    • 36749105984 scopus 로고    scopus 로고
    • A numerical master equation solution for the relaxation of a highly excited anharmonic oscillator appears to show much the same kind of single-component relaxation profile. Nesbitt, D. J, Hynes, J. T. J. Chem. Phys. 1982, 77, 2130
    • A numerical master equation solution for the relaxation of a highly excited anharmonic oscillator appears to show much the same kind of single-component relaxation profile. Nesbitt, D. J.; Hynes, J. T. J. Chem. Phys. 1982, 77, 2130.
  • 42
    • 0030284757 scopus 로고    scopus 로고
    • 1 times, but the relaxation process itself is still dominated by repulsive forces. See: Gnanakaran, S.; Lim, M.; Pugliano, N.; Hochstrasser, R. M. J. Phys.: Condens. Matter 1996, 8, 9201.
    • 1 times, but the relaxation process itself is still dominated by repulsive forces. See: Gnanakaran, S.; Lim, M.; Pugliano, N.; Hochstrasser, R. M. J. Phys.: Condens. Matter 1996, 8, 9201.
  • 45
    • 84906368789 scopus 로고    scopus 로고
    • If the total first solvation shell population is conserved, the kinetics is identical to standard A ↔ B chemical kinetics result, with A the innermost and B the outermost populations. The rate constant ka is then the sum of the forward and backward rate constants. See ref 1
    • a is then the sum of the forward and backward rate constants. See ref 1.
  • 46
    • 84906368785 scopus 로고    scopus 로고
    • This change turns our differential equation into a differential- difference (or delay-differential) equation. Saaty, T. L. Modern Nonlinear Equations; Dover: New York, 1981; Chapter 5
    • This change turns our differential equation into a differential- difference (or delay-differential) equation. Saaty, T. L. Modern Nonlinear Equations; Dover: New York, 1981; Chapter 5.
  • 47
    • 84906383160 scopus 로고    scopus 로고
    • In the limit that t0 → 0 and the second half of eq 4.4c is satisfied, α → kb/ka, γ → 0, and eq 4.9 reverts back to eq 4.6
    • a, γ → 0, and eq 4.9 reverts back to eq 4.6.
  • 48
    • 84906383161 scopus 로고    scopus 로고
    • The same equations can also be used to predict the time evolution of the solvent geometry not shown, At intermediate times, the results are not as accurate as those for the energy relaxation, but at long times they match the initial-rotational-energy dependence of the molecular dynamics reasonably well
    • The same equations can also be used to predict the time evolution of the solvent geometry (not shown). At intermediate times, the results are not as accurate as those for the energy relaxation, but at long times they match the initial-rotational-energy dependence of the molecular dynamics reasonably well.
  • 49
    • 84906368786 scopus 로고    scopus 로고
    • -1 initial rotation excitation in Figure 4 corresponds to 34 rotational periods of a classical free rotor.
    • -1 initial rotation excitation in Figure 4 corresponds to 34 rotational periods of a classical free rotor.
  • 55
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    • John Wiley: New York, Appendix C
    • Messiah, A. Quantum Mechanics; John Wiley: New York, 1958; Appendix C.
    • (1958) Quantum Mechanics
    • Messiah, A.1

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.