Anomalous energy effects

J, S. Murray,/. M. Seminario, P. Lane, and P. Politzer,/. Mol. Struct. (THEOCHEM), 207, 193 (1990). Anomalous Energy Effects Associated with the Presence of Aza Nitrogens and Nitro Substituents in Some Strained Systems. 

The possibility of the anomalous isotope effect for electron tunneling reactions was first noted by Ulstrup and Jortner [7]. This effect becomes possible when the reorganization energy is approximately equal to the reaction exothermicity. If, in this case, for example, the relationship Er - J + a) — 0 is satisfied, where co is the vibrational frequency for a heavy isotope, then from the viewpoint of the activation energy [see eqn. (42)1, the transition (0 - 1) is optimal for the heavy isotope. Compared with this transition for the heavy isotope, both the transitions (0 - 0)and(0 - 1) for the light isotope contain the additional activation multiplier. In this situation the anomalous isotope effect will be observed, provided that the Franck Condon factor for the transition (0 -> 1) of the heavy isotope is not too small compared with that of the light isotope. An example of the electron tunneling reaction for which the anomalous isotope effect is observed experimentally will be considered in Chap. 7, Sect. 4. 

As interesting as these special "exit-channel" effects are in their own right, it has been shown that because of a cancellation, they have no bearing on the MIF phenomenon [15]. We stress this point, since occasionally it is assumed in the literature that the special exit channel effect in the ratios is a key to understanding the MIF. Instead, the mass-independent effect of "scrambled" systems and the anomalously large mass-dependent effect for reactions of the type Q -F OO QOO QOO and QO -F O, have very different origins and are unrelated. Perhaps these remarks may seem paradoxical. The various rate constants for these "isotopically unscrambled" reactions can be used to compute the observables for the isotopically scrambled system, and so compute and 5 0. However, the detailed analysis [15] showed that there is much cancellation, summarized below, and that the theoretical expression for the MIF conditions is now simpler than would appear from fhe expression for the MIF in terms of the individual rate constants [15]. In particular, the zero-point energy effect, important for the individual isotope rate constants, disappears when the combination of them that determines the MIF is calculated. 

In conclusion, it is worth reiterating that the anomalous absorption effects described here may be manifest in any experiments that employ sufficiently high-intensity broadband radiation. To this extent, anomalies may be observable in experiments not specifically involving USES light. In particular, the continued advances in techniques of laser pulse compression have now resulted in the production of femtosecond pulses only a few optical cycles in duration (Knox et al. 1985 Brito Cruz et al. 1987 Fork et al. 1987) which necessarily have a very broad frequency spread, as the time/energy uncertainty principle shows. Thus, mean-frequency absorption may have a wider role to play in the absorption of femtosecond pulses. If this is correct, it raises further questions over the suitablity of absorption-based techniques for their characterization. 

As in the case of LAXS measurements, the anomalous dispersion effects, arising when the energy is closed to the absorption edge, can be used with the SAXS technique. FONTAINE did ASAXS experiments, at LURE-DCl, to probe the distribution of Zn atoms in phase separated Ai—Zn alloys He measured the variation of SAXS from Guinier-Preston zones when the energy is scanned below the Zn absorption edge (Fig. 5). 

In strong magnetic fields the magnetic energy of an atom will be higher than the splitting of the lines. Then the L-S interaction will become negligible and the anomalous Zeeman effect resembles the Zeeman triplet (the Paschen-Back effect). 

Those of us who worked with Martin Fleischmann likely remember him for different aspects of his multifaceted personality and extreme scientific diversity. For the authors of this chapter, his major accomplishment was the discovery of anomalous heat effects in the electrochemical palladium deuterium system (Pd/D). Few would have had the vision to see such a possibility, the courage to pursue it, and the skill to test it. These anomalous effects were and are consistent in magnitude with excess enthalpy production by nuclear reactions. These are several orders of magnitude larger than can be explained by chemical reactions or lattice storage energy. 

An El transition at 3125.66A connects the 6p and 6d D2 fine structure levels in Hg. A weak magnetic field splits these levels via the anomalous Zeeman effect. Evaluate the gj factors for both levels, indicate all of the El transitions that will occur using a schematic energy level diagram, and draw the resulting stick spectrum on a wavelength scale. 

Fig. 5. Comparison of electron energy loss spectra in N(E) form for clean Sm and Er metals at p 1 keV and 100 eV (Bertel et al. 1982b). Note the anomalous energy dependence in the plasraon region in Sm, an effect associated with surface divalency.

S. Luding, E. Clement, A. Blumen, J. Rajchenbach, and J. Duran. Anomalous energy dissipation in molecular-dynamics simulations of grains The "detachment effect". Physical Review E, 50(5) 4113-4120, 1994. 

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