Vibrational relaxation of molecules on alkali halide surfaces

Chang, Huan‐Cheng; Ewing, George E.

doi:10.1016/0368-2048(90)80199-k

Cited by 31 publications

(5 citation statements)

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“…The CO/NaCl(100) has also served as a model system for exploring the dynamics of vibrational energy flow at surfaces. , Extensive time-domain infrared spectroscopic measurements by Ewing and co-workers have revealed some interesting properties of vibrational energy flow within the CO monolayer on the NaCl(100) surface, including the phenomenon of vibrational energy pooling. − A mechanism for vibrational energy pooling in a gas phase system of diatomic molecules being optically pumped by a laser tuned to their fundamental vibrational absorption frequency was first proposed in 1968 by Treanor et al When a pair of diatomic molecules each in their first vibrationally excited state collide, a vibrational exchange reaction of the type AB(1) + AB(1) → AB(0) + AB(2) can occur. Anharmonicity in the bond vibration of the molecules results in the products being lower in energy than the reactants, the excess energy being transferred to the translations and rotations of the molecules after the collision.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Energy Pooling in CO on NaCl(100): Simulation and Isotope Effects

Corcelli

Tully

2002

J. Phys. Chem. A

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The phenomenon of vibrational energy pooling in a CO monolayer on a NaCl(100) surface is investigated using a kinetic simulation approach. The kinetic Monte Carlo (KMC) method requires as input the rate constants for each available channel of vibrational energy flow in the system: laser excitation; vibrational relaxation to the substrate; vibrational energy transfer between nearest neighbor CO molecules on the surface; radiation. These rates were computed using perturbation theory and available experimental information. Our simulations predict a dramatic isotope effect in which energy is seen to preferentially pool on heavier isotopomers of CO if a natural abundance sample of CO is optically pumped. Simulations of an isotopically pure CO/NaCl(100) system continuously pumped by a laser source demonstrate that vibrational energy pools containing more and more quanta can be formed by using more intense lasers until a theoretical crossover is reached where vibrational relaxation rates become faster than vibrational energy pooling rates. This crossover occurs at n ) 18 for 12 C 16 O. Finally, the effect of temperature on the vibrational dynamics in the CO/NaCl(100) system is explored with the result that finite temperature facilitates energy redistribution within the monolayer, hastening the overall vibrational relaxation dynamics.

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Section: Introductionmentioning

confidence: 99%

Vibrational Energy Pooling in CO on NaCl(100): Simulation and Isotope Effects

Corcelli

Tully

2002

J. Phys. Chem. A

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“…(39) and by inserting Eq. (36) in Eq. (14), the Laplace transform of the mean square displacement can be expressed in terms of t (q, z) (Eq.…”

Section: Interpretation and Discussionmentioning

confidence: 95%

“…For instance, the vibrational lifetime for the Si-H vibration for the system Si/H(111) is about 1 ns at room temperature [35]. A remarkable example is given by the stretching vibration of CO adsorbed on NaCl for which the lifetime was measured to be about 0.01 s [36]. In such molecular adsorbates, the dephasing time ranges typically between a few picoseconds and a hundred picoseconds.…”

Section: Model and Hamiltonianmentioning

confidence: 97%

Two-vibron bound states in a stochastic surrounding: Quantum breather diffusion

Pouthier

2006

Physica D: Nonlinear Phenomena

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“…+ H -H2 (9) They found no evidence for radicals promoting polymerization by C2H + C2H2 -C4H3 (10) However, H atoms do react with C2D233""36 in the gas phase as follows:…”

Section: Represent [C2d2] and [C2hd]mentioning

confidence: 99%

Photochemistry of acetylene physisorbed on sodium chloride: a temperature-dependent hydrogen-exchange reaction

Dunn¹,

Ewing²

1993

J. Phys. Chem.

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Results are presented for the photolysis of acetylene physisorbed to polycrystalline films of NaC1. We find evidence for two adsorbed phases of this system: a low-temperature structured phase and a high-temperature lattice gas. Upon exposure to 184.9-nm light, the high-temperature phase undergoes the hydrogen exchange C2H2 + C2D2 e 2C2HD, while the low-temperature phase is unreactive. In contrast to gas-phase photolysis, which yields a polymer, molecular hydrogen, and a collection of small hydrocarbons, no products other than acetylene isotopomers are observed in the surface-phase reaction. The rate of the reaction shows an exponential temperature dependence and is interpreted as being surface diffusion limited. We propose that this photochemical exchange occurs by a radical chain reaction.

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Vibrational relaxation of molecules on alkali halide surfaces

Cited by 31 publications

References 50 publications

Vibrational Energy Pooling in CO on NaCl(100): Simulation and Isotope Effects

Vibrational Energy Pooling in CO on NaCl(100): Simulation and Isotope Effects

Two-vibron bound states in a stochastic surrounding: Quantum breather diffusion

Photochemistry of acetylene physisorbed on sodium chloride: a temperature-dependent hydrogen-exchange reaction

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