Isothermal outgassing curves of hollow glass microspheres filled with helium, hydrogen, or deuterium gas have been determined. Four million 40–45-μm soda-lime glass microspheres, similar to laser-fusion targets, were filled by gas permeation at 693–763 K and outgassed at 292–573 K. The permeabilities were calculated by an exponential theory, and they agree to an order of magnitude with the literature values. The outgassing curves are not pressure dependent. Two irregularities are apparent. First, the counting of target-quality individual D-T–filled microspheres shows a permeability spread of an order of magnitude from one microsphere to the next, which may be caused by variable chemical composition. Second, all the gases show deviations from exponential behavior in the form of tails at long times. Chemical reaction of the hydrogen with the glass, as well as incomplete filling and outgassing, may cause the hydrogen tails; the cause of the helium tails is not known.

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Electrons in an atom are confined to distinct, quantized energy levels. When atoms form solids, the interaction of the electrons causes their energy levels to split into multiple closely spaced levels, or bands, separated by forbidden regions called band gaps. Each band contains a number of energy levels equal to the number of atoms in the solid. This model of the origin of band structure can be reproduced by using a classical array of harmonic oscillators (masses connected by springs). In this system, each oscillator plays the role of an atom and its resonant frequencies play the roles of electronic energy levels. When coupled, a system of oscillators yields a spectrum of resonant frequencies and when the number of oscillators becomes sufficiently large, the system exhibits the formation of “resonant frequency bands,” similar in structure to the energy bands of an atomic solid. We experimentally demonstrate band formation using coupled harmonic oscillators and highlight the effects of both number of oscillators and coupling strength on the band structure. Additionally, we show that experimental results of this band formation follow a theoretical analysis of the system.

The fundamental vibration–rotation spectra of condensed DT and T2 were measured. The 24 separate spectral lines identified consist mainly of QQ, QR, QQ+So(0), and QQ+So(1) transitions. The last two appear as triad sets in D2–DT–T2 solutions because of double transitions between different isotopes. The QQ frequencies are 2458 cm−1 for T2 and 2736 cm−1 for DT. Some approximate kinetic half-times have been measured. In the 21 K liquid, these include: 18 h for the reaction of D2+T2→2DT and 25 h for the T2 rotational J=1 to J=0 conversion. In solid T2 at 20 K, the J=1 to J=0 conversion time is also about one day, but it is only 1 h at 4 K. Catalysis by atomic tritium is considered to be the cause of the fast 4 K-conversion time.

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