Vibration thresholds

Figure 8. Translational energy distributions of CO(v = 0) after dissociation of H2CO at hv = 30,340.1 cm for the CO product rotational levels (a) Jco = 40, (b) 7co = 28, and (c) Jco = 15. The internal energy of the correlated H2 fragment increases from right to left. Dashed lines are translational energy distributions obtained from the trajectory calculations. Markers indicate H2 vibrational thresholds up to v = 4, and in addition odd rotational levels for v = 5—7. Reprinted from [8] with permission from the American Association for the Advancement of science.

Figure 17. Internal energy distributions of HCO from photodissociation of CH2O at 2549 cm (upper panel) and 2627 cm (lower panel) above the threshold for the H + HCO channel. The HCO vibrational thresholds are labeled with their quantum numbers, and combs label the stack thresholds. The open circles show predictions of the SSE/PST model. The upper panel is indicative of an So dominant pathway. In the lower panel, T is dominant, but So structure can still be observed. Reprinted with permission from [51]. Copyright 2000, American Institute of Physics.

H2+(Ne,H)NeH + 11 was demonstrated that this reaction possesses a vibrational threshold 99a... 

In the case of sharp resonances at the Fermi level (situation encountered in the case of magnetic impurities), the elastic contribution to the change in conductance will likely be the largest one, leading to a decrease of conductance above the vibration threshold. 

Mode assignment and symmetry selection rules. Equations (5) and (8) contain the matrix element (fi V v). When this matrix element is zero, the conductance at the vibration threshold will be zero. Hence, the symmetry of the electronic states p, and z/, and of the vibration can determine when this matrix element will be zero. 

Fig. 2. Reactive collision probabilities Pfrom ground state of the reactants, calculated by Truhlar and Kuppermann (1972), as functions of total energy E and relative kinetic energy E0. Arrows indicate vibrational thresholds. Crosses are results of Mortensen and Gucwa (1962) for P 0o), shifted to the left by 0-057 eV.

From the comparison of the photoionization-efficiency curves for H2, HeH and NeH", they were able to show that HeH and NeH" ions are produced by vibrationally excited H2 ions, the vibrational threshold being L = 3 and v = 2 for HeH and NeH formation, respectively, at zero kinetic energy. These thresholds are somewhat different from those obtained in the electron impact studies [161, 162] v = h and 2, respectively). Above the vibrational threshold, the reaction cross-section increases with vibrational quantum number and there is no kinetic energy threshold, in contrast with the result of Friedman and his co-workers who observe small kinetic energy thresholds for these vibrational states. 

The kinetic energy dependence of reaction cross-section above vibrational threshold obtained by Chupka and Russell [167] was also similar to that of Friedman and his co-workers except for some significant differences in the lowest kinetic energy region. 

Singh, P. K. (2000). Evaluation of damages to underground coal mines caused by surface blasting vis-a-vis establishment of blast vibration threshold (Project No GAP/III/ BLASTING/MOC/1996, pp. 1-50). CMRI Coal S T. 

Nerve conduction studies, vibration thresholds, quantitative G... 

The second kind of transition state resonance, as illustrated in Figure 23.20b, is known as the vibrational threshold resonance. This type of resonance corresponds to the energetic threshold for a quantized dynamical bottleneck in the transition-state region. This quasi-bound state can be characterized by two vibrational quantum numbers (for a three-atom system), corresponding to the modes of motion orthogonal to the unbound reaction coordinate. This kind of resonance has been found experimentally in... 

Here, the PES of the anion lies dose to, but below, the neutral surface, and the lowest vibrational levels of the dipole-bound anion are located just below the corresponding vibrational levels of the neutral. These long-lived VFRs appear as narrow features below the vibrational thresholds in elastic or vibrationally inelastic electron scattering cross sections (Hotop et al. 2003). VFRs may also decay through the dissociative electron attachment mechanism. For an excellent, detailed overview, see reviews by Schulz (1973a, b) and Hotop et al. (2003). 

See, however, F. E. Bartoszek, D. M. Manos, and J. C. Polanyi, Effect of changing reagent energy. X. Vibrational threshold energies for alternative reaction paths HF(v) f D F + HD and... 

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