The partial photoionization cross sections for the outer p subshell of the ground state of bromine are calculated in all available open channels as determined by LS coupling for photon energies from the 3 P to 1 S thresholds. The electron correlations which are important in this case have been taken into account using the multiconfiguration Hartree-Fock approximation for the bound and the continuum wave functions. The resonance structures between the 3 P and 1 D threshold and between the 1 D and 1 S threshold have been identified. In order to compare with experiment a frame transformation is applied to transform the LS dipole matrix elements to jj coupling. The calculated energy positions for the autoionizing resonances 4p 4 ( 1 D)md, 4p 4 ( 1 D)ns and 4p 4 ( 1 S)md and 4p 4 ( 1 S)ns are compared with recent experimental measurements, and are found to be in excellent agreement. ͓S1050-2947͑99͒10105-7͔PACS number͑s͒: 32.80.Fb, 32.80.Dz

The multiconfiguration Hartree-Fock method for continuum wave functions has been used to perform calculations of elastic scattering of electrons from the open-shell sulfur atom at low energies. The electron correlation and polarization of the sulfur atom by the scattered electron, which are very important in this calculation, have been taken into account very accurately ab initio through the configuration-interaction procedure by optimizing both bound and continuum orbitals simultaneously at each kinetic energy of the scattered electron. The scattering lengths, phase shifts, and differential, total and momentum-transfer cross sections for electrons elastically scattered from sulfur atoms are calculated for the impact-energy range from 0 to 27.2 eV. The wave functions computed exactly at zero energy are used to compute the scattering length. The present results are compared with other available theoretical results. ͓S1050-2947͑97͒08208-5͔

The partial and total photoionization cross sections from the initial 2 P 3/2 ground state of atomic Br to the final Br ϩ 3 P J components across the 4p 4 (1 D 2)6d,8s(2 P, 2 D, 2 F, 2 S) autoionization resonances are presented. The multiconfiguration Hartree-Fock ͑MCHF͒ method has been used to calculate both bound and continuum wave functions in the nonrelativistic limit. The Breit-Pauli approximation is applied to determine the effect of spin-orbit interactions in the photoionization of atomic Br with the MCHF wave function as input. Our calculated results are compared with experimental data.

In the extreme conditions of high altitude, low temperature, low pressure and high speed, the aircraft engine has a strong tendency to extinguish and it is then difficult to start secondary ignition, which means that re-ignition of the aircraft engine faces great challenges. Additionally, the ability of the single-channel gliding arc (1-GA) in assisting the ignition under extreme conditions is weak. In this paper, to solve this problem, a multichannel gliding arcs (MGA) system is proposed, using the principle of multichannel discharge. Experiments on the electrical characteristics and ignition performance of MGA were conducted under atmospheric pressure in a swirl model combustor. The electrical characteristics of MGA were investigated under different air velocities. The ignition process of MGA was recorded by using a high-speed camera with CH* filter. Results show that the three-channel gliding arcs (3-GA) and five-channel gliding arcs (5-GA) generated more averaged power than the 1-GA under a constant air velocity. For example, the 3-GA and 5-GA generated 112.8% and 187.3% more averaged power than that of the 1-GA at 74.6 m s−1, respectively. The arc shapes of gliding arcs with different channel numbers were different and the duration time of ‘breakdown-stretching-extinguishing’ of MGA shortened. Furthermore, compared with the 1-GA, the percentage of the lean ignition limit widening of the 3-GA and 5-GA can reach 13.5% and 20.9% respectively. The frequency of re-breakdown in the discharge process using different gliding arc channel numbers is different, which can continuously inject energy into the combustor and generate the ‘flame combination’ phenomenon producing a larger flame area. The ignition process of MGA can be divided into three stages: sliding stage, flame combination stage and flame stabilization stage.

The multiconfiguration Hartree-Fock (MCHF) method for continuum wavefunctions is used to study the photoionization of lithium and ions of its isoelectronic sequence for photon energies from 0.1 to 250 Ryd. Electron correlation and polarization effects in the initial and final states and relaxation and correlation in the final ionic states, which are found to be very important in the valence-and K-shell partial photoionization cross sections, have been taken into account accurately in an ab initio manner through the configuration interaction procedure. The present results are compared with available experimental measurements and accurate theoretical data for a limited energy range and are found to be in good agreement.