Three important transport coefficients, namely the ratio of the Townsend first ionization coefficient to the gas number density , the mean-arrival-time drift velocity and the product of the longitudinal diffusion coefficient and the gas number density , in methane have been experimentally determined over a wide range of E/N, E being the electric field and N the gas number density, from 0.2 to 2000 Td by a double-shutter drift tube method analysed by an arrival-time-spectrum (ATS) technique. Equilibrium of the electron energy at high values of E/N in the present experiment is confirmed by a Monte Carlo simulation for the same gas. The present values of and as a function of E/N agree well with those in the literature which were obtained by using techniques such as the steady-state Townsend experiment, time-of-flight analysis and a pulse experiment. This demonstrates the validity of the present drift tube method and ATS analysis. The present result for , however, agrees with that in the literature in the rough shape of variation with E/N only; it is found that there are differences of a few tens of percentage in the present values against the values in an earlier paper and that a local maximum and minimum found in the previous article do not exist.

An efficient total synthesis of aperidine was accomplished using a Rh-catalyzed C-H insertion of a cis-dihydrobenzofuran ring. To circumvent the facile epimerization of the cis-dihydrobenzofuran ring, we designed and prepared the C-H insertion precursor diazoamide by Raines' protocol. Finally, the efficient incorporation of a guanidine group and mild deprotection conditions yielded this labile natural product.

The ratio of the Townsend first ionization coefficient to the gas density , the mean-arrival-time drift velocity and the product of the longitudinal electron diffusion coefficient and the gas density in tetraethoxysilane (TEOS) vapour have been experimentally determined over a wide range of E/N from 14 to 6000 Td by a double-shutter drift tube technique using an arrival-time spectra (ATS) analysis. The result shows that the present values of are in excellent agreement with those previously measured by the steady-state Townsend method in an E/N range of 450 - 2000 Td. Values of and in the TEOS vapour are reported for the first time in the present paper. It is revealed that takes an almost constant value at 140 Td < E/N < 300 Td but monotonically increases in the other E/N ranges in the present measurement. The ratio of the longitudinal diffusion coefficient to the electron mobility is also deduced. The result shows that the mean electron energy in the TEOS vapour is very low, which suggests that inelastic collisions between electrons and the TEOS molecule occur more frequently even in a low-electron-energy region.

This paper reports four electron transport coefficients in tetramethylsilane (TMS, Si(CH3)4) vapour which is utilized in plasma-enhanced chemical vapour deposition (PECVD) of thin films such as SiC and SiN. The coefficients, namely the density-normalized effective ionization coefficient (αeff/N), the mean-arrival-time drift velocity (Wm) and the product of the longitudinal electron diffusion coefficient and the gas density (NDL) have been experimentally determined using a double-shutter drift tube method based on an arrival-time spectra theory over a reduced electric field (E/N) range of 30–5000 Td (1 Td = 10−21 V m2). The result shows that the coefficient αeff/N increases rapidly at an E/N value of about 200 Td and then reaches a value of 9.84 × 10−16 cm2 at an E/N value of 5000 Td. It is revealed that the values of the coefficient αeff/N are practically equal to those in SiH4 gas which is a representative gas used in PECVD. The reliability of the αeff/N values is checked by a steady-state Townsend experiment. The drift velocity (Wm) monotonically increases with E/N except at 50 Td < E/N < 200 Td, where a slight negative differential conductivity is observed. The longitudinal diffusion coefficient (NDL) has a minimum value at an E/N value of about 100 Td in the present measurement. Its variation profile against E/N is similar to that in SiH4 although its profile shifts to higher E/N. The ratio of the longitudinal diffusion coefficient to the mobility (DL/μ) is deduced from the Wm and the NDL values, which monotonically increases from 0.1 to about 10 eV with E/N in the present E/N range.