The spatial distributions of the electron density and the mean electron energy of argon radio frequency （rf） glow discharge plasma in a plasma-enhanced chemical vapour deposition （PECVD） system have been investiga...The spatial distributions of the electron density and the mean electron energy of argon radio frequency （rf） glow discharge plasma in a plasma-enhanced chemical vapour deposition （PECVD） system have been investigated using an established movable Langmuir probe. The results indicate that in the axial direction the electron density tends to peak at midway between the two electrodes while the axial variation trend of mean electron energy is different from that of the electron density, the mean electron energy is high near the electrodes. And the mean electron energy near the cathode is much higher than that near the anode. This article focuses on the radial distribution of electron density and mean electron energy. A proposed theoretical model distribution agrees well with the experimental one： the electron density and the mean electron energy both increase from the centre of the glow to the edge of electrodes. This is useful for better understanding the discharge mechanism and searching for a better deposition condition to improve thin film quality.展开更多
We set up a model for dealing with the second-harmonic generation （SHG） from molecular dipoles in a line alignment pattern rather than a planar distribution under a microscope. Because of this model, it is possible ...We set up a model for dealing with the second-harmonic generation （SHG） from molecular dipoles in a line alignment pattern rather than a planar distribution under a microscope. Because of this model, it is possible to perform a flexibly quantitative investigation of SHG from collagen fibres at a molecular level The line alignment pattern induces more significant modifications in both the angular dipole distribution structure A（θ, φ） and the second-harmonic power structure θ（θ, φ）, compared to a planar distribution. Also, the line Mignment angle t has strong effect on A（θ, φ） and θy（θ, φ）, resulting in an irregular SHG angular power distribution. That is to say, it is unnecessary for SHG emission to present two well-defined off-axis lobes. The total SHG power shows two symmetrical peaks at angles of t = 50° and t - 130° while a drop at t = 90°. The weakest SHG signals can be measured at t = 0° and t = 180°.展开更多
A closed form of the title integral formula over the Gaussian-type orbitals is derived for the first time. The present closed form is analytical as the multiple hyper-geometric function of five variables.
The ground and three low-excited states of the positronium negative ion Confined by a spherical harmonic oscillator potential are studied employing the adiabatic hyperspherical approach method. Total energies are obta...The ground and three low-excited states of the positronium negative ion Confined by a spherical harmonic oscillator potential are studied employing the adiabatic hyperspherical approach method. Total energies are obtained as a function of the confined potential radii. We find that the confinement may cause accidental degeneracies between levels with different low-excited states and the inversion of the energy wlues.展开更多
Using the optical-model, we theoretically investigate the positronium （Ps） formation in e^＋-Mg collision from the positronium threshold to 60.0eV. A complex equivalent local polarization potential is obtained to de...Using the optical-model, we theoretically investigate the positronium （Ps） formation in e^＋-Mg collision from the positronium threshold to 60.0eV. A complex equivalent local polarization potential is obtained to describe the rearrangement process, which reproduces Ps formation cross section. We report the total Ps （n = 1 ＋ 2） formation cross sections and compare them with the experimental measurements and other theoretical results.展开更多
文摘The spatial distributions of the electron density and the mean electron energy of argon radio frequency （rf） glow discharge plasma in a plasma-enhanced chemical vapour deposition （PECVD） system have been investigated using an established movable Langmuir probe. The results indicate that in the axial direction the electron density tends to peak at midway between the two electrodes while the axial variation trend of mean electron energy is different from that of the electron density, the mean electron energy is high near the electrodes. And the mean electron energy near the cathode is much higher than that near the anode. This article focuses on the radial distribution of electron density and mean electron energy. A proposed theoretical model distribution agrees well with the experimental one： the electron density and the mean electron energy both increase from the centre of the glow to the edge of electrodes. This is useful for better understanding the discharge mechanism and searching for a better deposition condition to improve thin film quality.
文摘We set up a model for dealing with the second-harmonic generation （SHG） from molecular dipoles in a line alignment pattern rather than a planar distribution under a microscope. Because of this model, it is possible to perform a flexibly quantitative investigation of SHG from collagen fibres at a molecular level The line alignment pattern induces more significant modifications in both the angular dipole distribution structure A（θ, φ） and the second-harmonic power structure θ（θ, φ）, compared to a planar distribution. Also, the line Mignment angle t has strong effect on A（θ, φ） and θy（θ, φ）, resulting in an irregular SHG angular power distribution. That is to say, it is unnecessary for SHG emission to present two well-defined off-axis lobes. The total SHG power shows two symmetrical peaks at angles of t = 50° and t - 130° while a drop at t = 90°. The weakest SHG signals can be measured at t = 0° and t = 180°.
文摘A closed form of the title integral formula over the Gaussian-type orbitals is derived for the first time. The present closed form is analytical as the multiple hyper-geometric function of five variables.
基金＊The project supported by National Natural Science Foundation of China under Grant No. 10475021 and the Natural Science Foundation of Guangdong Province of China under Grant No. 04009519
文摘The ground and three low-excited states of the positronium negative ion Confined by a spherical harmonic oscillator potential are studied employing the adiabatic hyperspherical approach method. Total energies are obtained as a function of the confined potential radii. We find that the confinement may cause accidental degeneracies between levels with different low-excited states and the inversion of the energy wlues.
基金Supported by the National Natural Science Foundation of China under Grant No 10374035, and the National Doctoral Foundation of the Ministry of Education China under Grant No 20020183054.
文摘Using the optical-model, we theoretically investigate the positronium （Ps） formation in e^＋-Mg collision from the positronium threshold to 60.0eV. A complex equivalent local polarization potential is obtained to describe the rearrangement process, which reproduces Ps formation cross section. We report the total Ps （n = 1 ＋ 2） formation cross sections and compare them with the experimental measurements and other theoretical results.
