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Radiative lifetimes of some of the levels in the Cu II 3d^94p and 3d^95s configurations have been measured to accuracies of 10–20% by using a delayed-coincidence technique. Relative line strengths for the 3d^94s-3d^94p and 3d^94p-3d^95s arrays have been determined both theoretically and experimentally. The theoretical line strengths are based on intermediate-coupling calculations, and the experimental ones are based on branching-ratio measurements and the J-file sum rule. Good agreement between the two sets of values is obtained; agreement is more satisfactory for the 4s-4p array than for the 4p-5s array. The experimental line strengths are estimated to be accurate to 10% for the 4s-4p array and to 30% for the 4p-5s array. Transition probabilities are determined by normalizing the experimental line strengths to an absolute scale by using the measured lifetimes.

Velocity-averaged de-excitation cross sections of He(3 1S, 3 3S, 3 1P, 3 3P) states by Ne were determined in the temperature range of 290 to 680 K using a time-resolved spectroscopy technique. All of these cross sections were found to decrease slowly with increasing temperature.

We have developed a measurement method for obtaining spatial distributions of absolute densities of CF and CF2radicals in a plasma reactor by combining single-path infrared laser absorption spectroscopy (IRLAS) and laser-induced fluorescence (LIF) techniques. This novel method has been successfully applied to the spatial distribution measurement of absolute densities of CF and CF2radicals in an electron cyclotron resonance (ECR) plasma reactor employing a tetrafluorocarbon gas (C4F8). It was found that CF radical densities were higher than CF2ones in the plasma region but lower outside the plasma region.

Silylene radicals (SiH2) in a 40-W 40-mTorr RF (13.56 MHz) SiH4/Ar plasma were detected by use of a laser-induced-fluorescence (LIF) technique. The observed SiH2density increased with increasing Ar partial pressure. The absolute SiH2density, estimated from the comparison of the LIF intensity with the intensity of Rayleigh scattering caused by N2molecules, is in the range of 109-1010cm-3.

Five recently measured ^4He I transitions involving nS, nP, and nD levels (n = 3–8, Δn = 0, 2) are compared with the oretical energy levels having estimated uncertainties that are comparable with those of the experimental results (~10^-3 cm^-1) [T. J. Sears, S. C. Foster, and A. R. W. McKellar, J. Opt. Soc. Am. B 3, 1037 (1986)]. The agreement between theory and experiment is generally good, but a considerable discrepancy exists for one transition.

Using a microwave cavity resonance technique, the electron density (ne) in a low-pressure (40-100 mTorr) RF (13.56 MHz) SiH4plasma and the electron loss rate in the afterglow were measured with varying SiH4fractions in the SiH4/Xe, /Ar, /He and /H2mixture gases. The behavior of electron temperature (Te) was estimated from the relative variations of the excitation rate constants (kem) for emissive rare-gas excited states, which were derived by combining the results of electron density measurements with optical emission measurements. The product kemnegenerally increased with increasing dilution but the behaviors of the individual kemand nediffer considerably for different mixture gases. The results were discussed in terms of energy and particle balance consideration. It was found that the dominant electron loss process in the afterglow is attachment and that the major attaching species is not SiHx(x=0-4) but some larger molecules produced in the plasma, even under the low-power (< about 5 W) conditions studied. The same attachment process was shown to have a significant role in determining Teand nein the active plasma.

The behaviors of electrons and negative ions in a low-pressure (100 mTorr) capacitively-coupled radio-frequency (13.56 MHz) NF3/Ar plasma have been studied at a low-power level (2-10 W) using a laser photodetachment technique combined with a microwave cavity resonance method for determining electron density. The wavelength dependent photodetachment measurement indicated that F-is the predominant negative ion species in the plasma. The negative ion density was higher than the electron density by a factor of ?50 at a NF3mixing ratio ras low as 1% and the negative-ion/electron density ratio further increased with increasing rmainly because of the decrease in the electron density. The overall change in the negative ion density in the studied range of 1%

Laser-induced fluorescence spectroscopy using a cw ring dye laser was applied to the detection of low-density SiH2in a low-power RF SiH4/Ar mixture plasma at 40 mTorr. The translational temperature of SiH2in the plasma was determined from the excitation line profile and was found to be near room temperature irrespective of the SiH4mixing ratio.

The silylene ( SiH2) density in a parallel-plate RF (13.56 MHz) discharge using monosilane ( SiH4) gas has been measured by using laser-induced fluorescence spectroscopy. The effect of Xe, Ar, He and H2dilution gases on the SiH2density was investigated at a total gas pressure of 40 mTorr. In all dilution cases, the SiH2density was relatively insensitive to the SiH4fraction (x) in the mixtures for x\gtrsim0.5; however, except in the case of H2dilution, marked increase of the SiH2density was observed with decreasing xfor x\lesssim0.5. The production and loss mechanisms for SiH2are discussed on the basis of the observed SiH2density and supplementary optical emission measurements. The results indicate that, in highly diluted (x\lesssim0.1)SiH4/Xe and SiH4/Ar mixtures, the production of SiH2via energy transfer from excited Xe and Ar atoms to SiH4is dominant over direct electron impact dissociation of SiH4.