A 10.6 ym C02 laser operating a power range S P 200 watts was used to pump some select vibrational transitions in the NO2 molecule while monitoring the rotational transitions (91/9—'100/10), (232f 22 ~~"*242,23> ' (402,38 "393,37) in the (0, 0, 0) vibrational level and the (8q,8—*"^1,7) rotational transition in the (0, 1, 0) vibrational level. These rotational transitions were monitored by microwave probing to determine how the population of states in the rotational manifolds were being altered by the laser. Coincidences between some components of the V3-V2 band of N02 and the C02 infrared laser lines in the 10 um region appeared to be responsible for the strong interaction between the continuous laser beams and the molecular states.

We present a comparative theoretical study of the transient grating coherent effects in resonant picosecond excitation-probe experiments. Signals in both the probe and conjugate directions are discussed. The effects of recombination, non-radiative scattering and spatial and orientational diffusion are included. The analysis is applied to both a molecular and to a semiconductor model. Signal contributions from concentration and orientational gratings are distinguished and their temporal natures discussed. The theory is used to explain our recent observations in germanium. Included are discussions of picosecond transient grating self-diffraction measurements that can be understood in terms of an orientational grating produced by anisotropic (in k-space) state-filling. Though there have been predictions and indirect experimental evidence for isotropic state-filling in germanium, this is the first direct experimental indication of anisotropic state-filling in a semiconductor.

This article discusses direct ionization and electron capture in M-shell x-ray production by fluorine ions.

Article on ₁¹H+ and ₂⁴He+ -induced M-shell x-ray-production cross sections for selected elements in the rare-earth region.

A new method is developed for treating atoms and molecules in a magnetic field in a gauge-invariant way using the Rayleigh-Ritz energy variational principle. The energy operator depends on the vector potential which must be chosen in some gauge. In order to adapt the trial wave function to the gauge of the vector potential, the trial wave function can be multiplied by a phase factor which depends on the spatial coordinates. When the energy expectation value is minimized with respect to the phase function, the equation for charge conservation for stationary states is obtained. This equation can be solved for the phase function, and the solution used in the energy expectation value to obtain a gauge-invariant energy. The method is applicable to all quantum mechanical systems for which the variational principle can be applied. It ensures satisfaction of the charge conservation condition, a gauge-invariant energy, and the best upper bound to the ground-state energy which can be obtained for the form of trial wave function chosen.

This article discusses fast diffusion of As in polycrystalline silicon during rapid thermal annealing.

This article discusses rapid idothermal annealing of As-, P-, and B-implanted silicon.

The picosecond optical response of five thin germanium samples was measured following intense optical excitation using two variations of the excitation and probe technique. Seven-picosecond laser pulses of wavelength 1.054 um were used to measure the optical transmission of the samples for a variety of probe delays, excitation fluences, and sample temperatures. These parametric experiments were performed in an effort to determine if carrier cooling, carrier diffusion, or carrier recombination dominates the carrier dynamics immediately following excitation. The studies of a 5.7 um thick sample indicated that Auger recombination does not dominate the carrier dynamics, but that the carriers most likely cool immediately to within a few optical phonons of the lattice temperature. Lattice heating may also occur depending on excitation level. Neither cooling nor diffusion was ruled out as a major contributor to the transient optical response. A numerical analysis indicated that, although diffusion may be minimized in the thinner samples, the importance of surface recombination increases as the sample thickness decreases. The lattice temperature dependence of the optical transmission was found not to be in disagreement with the known temperature dependence of the low-density diffusion coefficient. Finally, new structure was observed in the data which is consistent with …

Article discussing L-shell x-ray production cross sections of Ni, Cu, Ge, As, Rb, Sr, Y, Zr, and Pd by (0.25-2.5)-MeV protons.

Article discussing K-shell x-ray production by 0.5-2.5-MeV ₄⁹Be+ ions incident upon selected elements from fluorine to potassium.

This article discusses multiple outer-shell ionization effect in inner-shell x-ray production by light ions.

Article discussing research on carbon K-shell x-ray and Auger-electron production in hydrocarbons and carbon oxides by 0.6-2.0-MeV protons.

Article discussing research on L- and M-shell x-ray production cross sections of Nd, Gd, Ho, Yb, Au, and Pb by 25-MeV carbon and 32-MeV oxygen ions.

This article discusses M-shell x-ray production cross sections for 0.5-2.5-MeV Be+ ions incident upon selected elements from praseodymium to bismuth.

Article discussing K-shell x-ray-production cross sections in 6C, 8O, 9F, 11Na, 12Mg, and 13AI, by 0.75- to 4.5-MeV protons.

Corrections to an equation printed with a typographical error in Quantum Irreversibility and Chaos, Physical Review Letters 67, 2593 (1991).

Article on direct evidence for the amorphous silicon phase in visible photoluminescent porous silicon.

Article on semiclassical chaos, the uncertainty principle, and quantum dissipation.

Article on phonon softening and high-pressure low-symmetry phases of cesium iodide.

This article discusses scanning tunneling microscopy of the electronic structure of chemical vapor deposited diamond films.

Article discussing the fabrication of silicon-based optical components for an ultraclean accelerator mass spectonomy negative ion source.

This article discusses the observation of silicon nanocrystals in siloxene using high resolution transmission electron microscopy.

This article contains visual observation data of the carbon star VY Ursae Majoris.

Article discussing research on control of chaos in a CO2 laser.