Hydrogen vibrationally excited from

Color from Vibrations and Rotations. Vibrational excitation states occur in H2O molecules in water. The three fundamental frequencies occur in the infrared at more than 2500 nm, but combinations and overtones of these extend with very weak intensities just into the red end of the visible and cause the blue color of water and of ice when viewed in bulk (any green component present derives from algae, etc). This phenomenon is normally seen only in H2O, where the lightest atom H and very strong hydrogen bonding combine to move the fundamental vibrations closer to the visible than in any other material. 

Fig. 7. Predicted diffusion coefficients for hydrogen (H) and deuterium (D) in niobium, as calculated by Schober and Stoneham (1988) from a model taking account of tunneling between various states of vibrational excitation and comparison with experimental measurements (solid lines). Theoretical curves are shown both for a model using harmonic vibrational wave functions (dashed lines) and for a model with anharmonic corrections (dashed-dotted lines).

Chemiluminescence is observed from several different emitting species, depending on the analyte and reaction conditions. Vibrational overtone bands of HF in the wavelength region of =500-900 nm are observed under nearly all conditions and are often the dominant spectral feature, the (3,0), (4,0) (5,1), and (6,2) bands being the most intense, while for some reaction conditions emissions from levels up to v = 8 are observed [63], It is likely that hydrogen atoms are produced in the reaction and form vibrationally excited HF in the reaction reported by Mann et al. [62] ... 

An alternative LIS scheme is one in which a vibrationally excited molecule reacts preferentially with another species. An example is the hydrogen halide/olefin addition reaction, DX + RiR2C = CH2 RiR2CXCH2D. The scheme involves sequential absorption of several quanta from a C02 laser near 5 p,m to selectively excite DX to a vibrational quantum number of 3 or more. Successful implementation would be expensive because of the highly corrosive nature of halogen acids. 

These data led to the model already described several times above. The enzyme executes a search for a tunneling sub-state, apparently 13 kcaFmol in energy above the principal state from this state the hydrogen atom tunnels with no further vibrational excitation. Probably motion of the secondary center is coupled into the tunneling coordinate. The result is large, temperature-independent primary and secondary isotope effects in the context of an isotope-independent activation energy. 

It emerges from this finding that the entire energy generated by these reactions does not go into vibrational excitation of the W-C bonds when the hydrogen sites are replaced by steps lb and 2a from Table 1. Over half of the species survive in a 36 step free radical reaction. Each of these steps generates, of the order of, 100 kcal mol-1 of energy. 

Above it was pointed out that in unmixed rare gases binary absorption does not exist because of the inversion symmetry of like pairs. For like molecular pairs inversion symmetry does in general not exist because of the anisotropic structure and vibrational excitations of the individual molecules. In Chapter 5, we will show that in pure hydrogen gas, for example, the translational spectrum arises mainly from orientational ( magnetic ) transitions the translational spectrum of H2-H2 is discernible in Fig. 3.10 at low frequencies (0 < v < 250 cm-1). The translational peak is weak if compared to the strong So(J) lines near 354 and 587 cm-1, but its strength is comparable to those of the dissimilar rare gas pairs, Fig. 3.1. The translational H2-He pair spectra are somewhat stronger, Fig. 3.12,... 

Cashion and Polanyi83 and Clement and Ramsay96 examined the red emission from about 6000 to 10,000 A resulting from the chemiluminescent reaction of hydrogen atoms with nitric oxide. The former authors observed emission from both vibrationally excited (2.9-3.6 p.)... 

Figure 19- Photoionization efficiency curves for production of H2+ and HeH+ from mixture of hydrogen and helium. Threshold energies for formation of Hj" in vibrationally excited states are indicated at top of figure.85 ...

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