Energy gaps experimental sources

We first take a brief look at the recent progress of experimental methods in a conceptual manner, and then consider what and how we can do theoretically to enhance the progress. Before starting though we note that the present chapter is not dedicated to an introduction to the vast field of photochemistry or excited-state chemistry, in which usually rather weak optical source is applied in a level of weak perturbation and create an excited state with a timed wavelength resonant to the relevant energy gap. Also, the recent extensive progress in nonlinear optics and its applications to molecular science will be mentioned here. 

There have been remarkable advances in synchrotron radiation research and related experimental techniques in the range from the vacuum ultraviolet radiation to soft X-ray, where the most important part of the magnitudes of these cross-section values is observed, as shown below. Therefore, it is also concluded that synchrotron radiation can bridge a wide gap in the energy scale between photochemistry and radiation chemistry. Such a situation of synchrotron radiation as a photon source is summarized in Fig. 1 [5,6]. 

The experimental observations are that approximately the same amount of decomposition was observed for 0.1 cm of air, Krypton, methane, or vacuum. Our most favorable calculations indicate that heat conduction alone is insufficient to cause appreciable reaction in air or vacuum and that the methane filled gap should give TNT temperatures at least 300°K lower than the Krypton-filled gap. Therefore, it would appear that some phenomenon other than plane surface heat conduction dominates the initiation process of explosives when gaps are present. Some mechanism is required for heat in the gas to be concentrated in local areas of the explosive surface, or some other source of initiation energy is required such as shock interactions or internal void compression. The concentration mechanism appears to be relatively independent of the gas temperature and essentially independent of the gas. 

---