NH radicals and H atoms were identified as products in the reaction of N(2D) with CH4. The absolute yields of NH and H were determined to be 0.3±0.1 and 0.8±0.2, respectively. The rotational state distributions of NH (v″=0) for CH4 and partially deuterated methanes, CHnD4−n (n=1–3), are single modal and peak at N″=13±2, while the vibrational population ratios, NH (v″=1)/NH (v″=0), are 0.6. The rotational energy distribution of ND (v″=0) from CD4 is similar to that for NH (v″=0). The ND (v″=1)/ND (v″=0) ratio is 0.6. Doppler profiles of H and D atoms were measured to evaluate the energy released to the translational mode. It was between 72 and 85 kJ mol−1, suggesting the following H atom production mechanism: N(2D)+CH4→H+CH2NH. The H+CH3N channel is minor. In the reactions with partially deuterated methanes, the isotopic ratios, [H]/[D] and [NH]/[ND], are larger than the stoichiometric ratios in the reactant methanes. These results suggest that C–H bonds are more reactive to N(2D) than C–D bonds, while H atoms are ejected more preferentially than D atoms.

Radical species produced in catalytic chemical vapor deposition (CVD), often called hot-wire CVD, processes were identified by using a laser induced fluorescence technique. Ground state Si atoms could be detected at low pressures where collisional processes in the gas phase could be ignored. The electronic temperature of Si atoms just after the formation on the catalyzer (tungsten) surfaces was 1320±490 K, when the catalyzer temperature was 2300 K. By the addition of 0.5 Pa of Ar, the electronic temperature was lowered down to 450±30 K. The absolute density of Si atoms was 3±1×109 cm−3 at 10 cm below the catalyzer when the flow rate and the pressure of SiH4 were 0.5 sccm and 4 mPa, respectively. This density is just 0.3% of that of the parent SiH4 molecules. However, since the decay rate of Si atoms is fast, it can be concluded that atomic silicon is one of the major products on the heated catalyzer surfaces. SiH radicals could also be detected, but the production rate of this species is two orders of magnitude less than that of Si atoms. It was also discovered that volatile SiH4 molecules are produced by the atomic hydrogen attack on the amorphous silicon deposited on the chamber walls.

The reaction pathways of N(2D) with methanol and its isotopomers were specified by laser pump-and-probe experiments and molecular orbital calculations. It was shown experimentally that CH3OH deactivates N(2D) efficiently to produce ground-state NH and OH radicals. The nascent state distributions of these radicals are not statistical, suggesting that the intermediate species decompose before energy randomization. A similar result was obtained for ND and OD formed in the N(2D)/CD3OD system. NH, ND, OH, and OD radicals were identified in partially deuterated systems. The ND/NH population ratio measurements show that NH and ND radicals are produced from both hydroxyl and methyl positions, but the former plays more important roles, one order of magnitude, than the latter. This is consistent with the result of ab initio molecular orbital calculations that the most favorable initial step is the addition of N(2D) to the O atom. The OD/OH ratio in the CD3OH system as well as the OH/OD ratio in the CH3OD system is 0.5. OH(OD) is produced mainly by the C−O bond scission just after the insertion of N(2D) into a C−H(C−D) bond, but the bond scission after intramolecular H/D scrambling is also important. This is also consistent with the result of calculations that the barrier height for the H(D) atom migration is much lower than the available energy.

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