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We numerically investigate electron transfers in nanowires which consist of deoxyribonucleic acid (DNA) molecules (up to five base pairs for double-strands and seven bases for single-strands) by quantum dynamical calculations. DNA molecules are applied to organic nanodevices and the performance depends on electronic transfer properties. Combining quantum chemical molecular-orbital calculations and stochastic mechanics, we provide an analyzing method of quantum dynamical electron motions. From one-electron wavefunctions or molecular orbitals, we calculate some dynamical properties, such as mean-square displacement and self-diffusion coefficients relating with electron mobility. Our calculation suggests that the electron transfers through the double-strands of GC base pairs while the electrons are localized in the double-strands of AT base pairs nor the single-strands of G bases.

The performance of a new structure plasma display panel (PDP) cell with counter sustain electrodes was diagnosed by optical emission and laser absorption spectroscopic measurements of the spatiotemporal behaviours of the microplasma. Two different types of panels were prepared: one with sustain electrodes only and the other with additional data and auxiliary electrodes on the rear and front plates. By using cells of the former type, the basic performance was measured as the dependences on the Xe concentration in Ne, the total pressure and the applied sustain voltage. It was seen that a higher Xe concentration was advantageous for the luminous efficiency although the required minimum sustain voltage became larger. By using the latter type of cell, the effects of driving schemes were investigated by varying the applied potentials onto the auxiliary and data electrodes. It was found that the role of the auxiliary electrode is remarkable; the discharge expands largely in the cell when the voltage and the width of the pulses applied to the auxiliary electrode are optimized to be 200 V and 0.3 µs, respectively, while the data electrode is grounded. The production efficiency of Xe atoms in the metastable (1s5) and resonance (1s4) states was derived from the measured absolute densities normalized by the input power per cell and the decay rates of those densities. The vacuum ultraviolet emission efficiency estimated from the results was compared between the tested conditions, and a noticeable improvement was recognized in the optimized condition, about 40% larger than a conventional driving condition without additional pulses. It was also seen that this cell structure is potentially superior in luminous efficiency to the conventional coplanar structure currently used in commercial PDPs.

Transient discharges in air that are started at undervoltages by supplying a large number of initial electrons at the cathode of parallel plates are investigated at gas pressures of 20 and 200 Torr. The discharge current has been measured, and factors affecting the development of the current are investigated by comparing the experimental current with a computer-simulated current. The spatiotemporal development of the electron, positive-ion and negative-ion densities and of the electric field are also calculated to account for the mechanism of breakdown. It is found at 200 Torr with E/p between 43 and 46 V cm-1 Torr-1 that the electrons produced in the gas by electron detachment have a large effect on the process of the space charge accumulation, which eventually leads to breakdown, while the cathode photoemission ( gamma p) effect is the main secondary process contributing to the space charge accumulation and breakdown at 20 Torr with E/p between 76 and 84 V cm-1 Torr-1.

The behaviour of electron avalanches in argon when appreciable electron impact ionization occurs, is studied by a Monte Carlo simulation. The values of electron swarm parameters are obtained for steady-state Townsend, pulsed Townsend and time-of-flight experiments, by applying sampling techniques appropriate to the respective experiments. The results suggest that the value of an electron swarm parameter, such as the ionization frequency or the electron drift velocity, depends on the type of experiments for which there is appreciable electron impact ionization. The properties of electron avalanches in an electron energy non-equilibrium region, for example the variation of the electron energy distribution with distance from the cathode, and the effect of anisotropic scattering of electrons on the swarm parameters very close to the anode, are also studied.

For pt.I see ibid., vol.10, no.7, p.1035 (1977). The electron swarm parameters for the steady-state Townsend, pulsed Townsend and time-of-flight experiments are calculated using a Boltzmann equation for argon at E/N values from 85 to 566 Td, when electron impact ionization is appreciable. The results suggest that the value of an electron swarm parameter depends on the type of the experiments involved, because of the presence of the ionization, in agreement with the Monte Carlo simulation work in the previous paper. The drift velocities and diffusion coefficients when ionization is present, are discussed.

Calculations of the three-body attachment coefficient eta3/N, N being the gas number density, in oxygen and an air-like nitrogen and oxygen mixture, are performed using a Boltzmann equation method. First, an appropriate cross-section Qa3for this attachment process in oxygen is deduced by modifying that of Spence and Schulz (1972) so that the calculated eta3/N agrees well with the experimental values of Grunberg (1969). Then, the deduced Qa3is used for the calculation of eta3/N in an air-like mixture of 79% nitrogen and 21% oxygen. Good agreement is obtained with the eta3/N values measured for dry air by Hessenauer (1967) at low E/N, where E is the electric field. The variation of eta3/N2with N is studied, and it is found that even though the value of Qa3is assumed to be proportional to N, eta3/N2can decrease with increasing N due to the change in the electron energy distribution, caused by the variation of Qa3.

Properties of the O- and O2- ion swarm in oxygen are studied by a Monte Carlo simulation technique for E/N values from 5 to 200 Td (1 Td=0.354 V cm-1 Torr-1 at 0 degrees C). The generation and loss reactions of the ions, such as dissociative attachment, electron detachment and charge transfer, as encountered in electron avalanches in oxygen, are taken into account. The results show that the values of the ion mobility, diffusion coefficients and detachment and charge transfer coefficients are in reasonable agreement with experiments. With O- ions the drift velocity, defined as the centre-of-mass velocity of an ion swarm, is found to be smaller than that defined as the velocity averaged in the velocity space, as E/N>or approximately=80 Td.

Electron swarm parameters in CO2 laser gas mixtures have been analysed for a range of the ratio of electric field to gas number density E/N from 2.83 to 283 Td (E/p0=1-100 V cm-1 Torr-1 at 0 degrees C) by a Boltzmann equation method in which the effect of electron impact ionisation and attachment can be considered properly (Thomas 1969, Tagashira et al. 1977, Taniguchi et al. 1977). Gas mixtures of CO2, N2 and He with concentration ratios of the respective gases of 1:1:8, 1:7:30, 1:1:3 and 1:2:3 are studied. The dissociation and dissociative ionisation processes for CO2 have been taken into account in addition to the electron collision processes considered in a previous study of Lowke et al. (1973). The results show that the present values of the ionisation coefficient and of the ratio of electron diffusion coefficient to mobility for the steady-state Townsend experiment are by about a few tens of percent lower than the previous theoretical values of Lowke et al. at high E/N values, but are in good agreement with recent experimental values of Lakhsminarasimha et al. (1976) for the whole E/N range studied. The excitation coefficient for the vibrational levels, important for the CO2 laser action, and the electron attachment coefficient are also calculated and discussed.

The variation of the steady state electron mean energy between parallel plates in argon and, for comparison, helium gases has been calculated as a function of the distance from the cathode by a Monte Carlo simulation applying a new technique of sampling steady state localized swarm parameters. A brief preliminary survey for excitation and ionization collision cross sections for argon has been made. The results show that, in both gases, damped oscillatory fluctuations of the electron mean energy follow its initial linear increase from zero energy at the cathode and that a rapid rise above the equilibrium energy occurs in front of the anode. This behaviour has been explained qualitatively in terms of an electron energy balance equation. Position dependent, diffusion modified localized drift velocities are also obtained in connection with the explanation.

Recent experimental work suggests that the simultaneous generation of more than one initial electron by a single irradiation particle in a discharge gap has important effects in the statistical distribution of breakdown time-lags by the Townsend mechanism. To take account of these effects, earlier theories, as given by Legler, are extended in the present paper. General formulae for time-lag distributions are obtained and typical numerical examples are compared with a digital computer simulation study to confirm the consistency of the calculations and to find the limitation due to approximation. An approximate, but direct, method of measuring the formative time-lag distribution when breakdown is initiated by a single electron is suggested.

Measurements on ion-induced liquid motion, which are necessary for the accurate determination of true ion mobilities, have been made using a laser-Doppler method. This method enables one to measure localized flow velocity with little effect on the system. It has been found that the bulk motion is influenced by the electrode geometry, the voltage polarity and the strength of the applied field.