Vibrational excitation of molecules

Faubel M and Toennies J P 1977 Scattering studies of rotational and vibrational excitation of molecules Adv. Atom. Mol. Phys. 13 229... 

All the above-mentioned experiments dealt with vibrational excitation of molecules by infrared laser lines. Inelastic collision processes in excited electronic states of molecules can be investigated in a similar way by means of visible or ultraviolet laserlines. 

Third, ultrashort laser pulses can provide for selective electronic or vibrational excitation of molecules, which will probably allow one to effect a high selective excitation of certain vibrational degrees of freedom, that is, to effect mode-selective photochemical reactions. 

Schneider, B.I. (1976). Role of the Born-Oppenheimer approximation in the vibrational excitation of molecules by electrons, Phys. Rev A 14, 1923-1925. 

The chain of reactions, which played the key role in these arguments, was, firstly, a vibrational excitation of molecules by electron impact (through resonant H2 levels), then, secondly, an ion conversion p + Ho(v) —> II If), followed by, thirdly, an immediate dissociative recombination e + H. — H + H. The excited atom decays by spontaneous emission. At the end of this chain, one electron-ion pair has recombined into an H-atom, and the H2 molecule has dissociated into H + H. 

The chain of reactions which plays a key role in MAR is the vibrational excitation of molecules by electron impact, then an ion conversion H2(w) + H+ —> + H, followed by dissociative recombination + e — ... 

E.E.Nikitin, Nonadiabatic vibrational excitation of molecules, Optika i Spektr. 9, 16 (1960)... 

Scattering Studies of Rotational and Vibrational Excitation of Molecules, Manjred Faubel and J. Peter Toennies... 

The Vibrational Excitation of Molecules by Electron Impact, D, G. Thompson Vibrational and Rotational Excitation in Molecular Collisions, Manfred Faubel Spin Polarization of Atomic and Molecular Photoelectrons, N. A. Cherepkov... 

Although the relationship between different plasma temperatures in non-thermal plasmas canbe quite sophisticated, it canbe conventionally presented in the collisional weakly ionized plasmas as > E > E Ti Tq. Electron temperature (Te) is the highest in the system, followed by the temperature of vibrational excitation of molecules (TV). The lowest temperature is usually shared in plasma by heavy neutrals (To, temperature of translational... 

Rate coefficients of the detachment process, which are especially important in the quasi-equilibrium thermal systems, are presented in Table 2-8. The kinetics of the detachment process can be described in this case in the conventional manner for all reactions stimulated by the vibrational excitation of molecules. The traditional Arrhenius formula, kd a exp(—fa/ Tv), is applicable here. The activation energy of the detachment process can be taken in this case to be equal to the electron affinity to oxygen molecules (E 0.44 eV). 

Table 2-15. Cross Sections of Vibrational Excitation of Molecules by Electron Impact...

LeRoy Formula and a-Model. Derive the general relation (2-205), describing the stimulation of chemical reactions by vibrational excitation of molecules, by averaging the LeRoy formula over translational energy E. Use the Maxwellian function for the distribution of molecules over translational energies. 

Distributions controlled by vibrational excitation. Vibrational excitation of molecules by electron impact strongly affects EEDF in molecular gases when Pev Assuming Pev( ) = const in the energy interval ei < e < 62 and X = const (Ven = j), the EEDF in the energy interval si < e < 62 is... 

Energy Efficiency of Plasma-Chemical Processes Stimulated by Vibrational Excitation of Molecules... 

Explain why plasma-chemical reactions can be effectively stimulated by the vibrational excitation of molecules only if the specific energy input exceeds the critical value, whereas reactions related to electronic excitation or dissociative attachment can be equally effective at any levels of specific energy input. 

Langmuir Plasma Oscillations and Molecular Oscillations. Calculate the plasma density required to reach the resonance condition between plasma oscillations and the vibration of molecules. Is it possible to use such resonance for direct vibrational excitation of molecules in plasma without any electron impacts ... 

The most energy-effective mechanism for plasma-chemical NO synthesis is provided by the vibrational excitation of molecules, because most of the energy of non-equilibrium discharges is transferred from electrons to vibrational excitation of N2 molecules at Te =... 

Possible Specific Contribution of Vibrational Excitation of Molecules to Ozone Synthesis in Pulsed Corona Discharges... 

Figure 6-39. Effect of vibrational excitation of molecules on G-factor of ozone synthesis in atmospheric-pressure pulsed corona discharges in air as function of specific energy input (1) taking into account the contribution of the effect of saturation of vibrational excitation (2) total contribution of vibrational excitation including the cross-sectional effect.

The chain of reactions can be accelerated by vibrational excitation of molecules. The typical reaction time is about 0.1 ms and is much faster than ion-ion recombination (1-3 ms), which determines the termination of the chain. As the negative cluster size increases, the probability of reactions with the vibrationally excited molecules decreases because of an effect of vibrational-translational (VT) relaxation on the cluster surface. When the particle size reaches a critical value (about 2 nm at room temperature) the cliain reaction of cluster growth becomes much slower and is finally stopped by the ion-ion recombination process. The typical time for 2 nm particle formation by this mechanism is about 1 ms at room temperature. A critical temperature effect on particle growth is partially due to VT relaxation, which depends exponentially on translational gas temperature according to the Landau-Teller effect (Section 2.6.2). Even a small increase of gas temperature results in a reduction of the vibrational excitation level and decelerates the cluster growth. 

Schultz, G.I (1976), Vibrational Excitation of Molecules by Electron Impact at Low Energies, in Principles of Laser Plasma, Bekefi, G. (ed.), John Wiley Sons, New York. 

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