The aim of this paper is to obtain relevant sets of collision cross sections of the parent ions in low pressure discharges in argon, oxygen, and nitrogen, i.e., Ar＋ in Ar, O2＋ in O2 and N2＋ in N2. These ion data ar...The aim of this paper is to obtain relevant sets of collision cross sections of the parent ions in low pressure discharges in argon, oxygen, and nitrogen, i.e., Ar＋ in Ar, O2＋ in O2 and N2＋ in N2. These ion data are first discussed and then validated from comparisons between the calculated transport coefficients and those measured in the literature. The elastic momentum transfer collision cross sections are determined from a semi-classical approximation for the phase shift calculation based on a 12-6-4 inter-particle potential while ion transport coefficients are determined versus the reduced electric field from Monte Carlo simulations.展开更多
By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional ener...By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional energy transfer is presented. Calculated results in Xe-Kr system show that in the present system, the laser-induced collision process occurs for -4 ps, which is much shorter than the dipole-dipole laser-induced collisional energy transfer （LICET） process. The spectrum of laser-induced quadrupole quadrupole collisional energy transfer in Xe-Kr system has wider tunable range in an order of magnitude than the dipole-dipole LICET spectra. The peak cross section decreases and moves to the quasi-static wing with increasing temperature and the full width at half peak of the profile becomes larger as the system temperature increases.展开更多
A four-state model considering the relative velocity distribution function for calculating the cross section of laserinduced collisional energy transfer in a Sr Li system is presented and profiles of laser-induced col...A four-state model considering the relative velocity distribution function for calculating the cross section of laserinduced collisional energy transfer in a Sr Li system is presented and profiles of laser-induced collision cross section are obtained. The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry. Both of the two intermediate states have contributions to the final state, and none of the intermediate states should be neglected. The peak of the laser-induced collisional energy transfer （LICET） profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing. A cross section of 1.2 × 10^-12 cm2 at a laser field intensity of 2.17 ×107 V/m is obtained, which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state. The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process, which is not accounted for in a two-state treatment.展开更多
文摘The aim of this paper is to obtain relevant sets of collision cross sections of the parent ions in low pressure discharges in argon, oxygen, and nitrogen, i.e., Ar＋ in Ar, O2＋ in O2 and N2＋ in N2. These ion data are first discussed and then validated from comparisons between the calculated transport coefficients and those measured in the literature. The elastic momentum transfer collision cross sections are determined from a semi-classical approximation for the phase shift calculation based on a 12-6-4 inter-particle potential while ion transport coefficients are determined versus the reduced electric field from Monte Carlo simulations.
文摘By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional energy transfer is presented. Calculated results in Xe-Kr system show that in the present system, the laser-induced collision process occurs for -4 ps, which is much shorter than the dipole-dipole laser-induced collisional energy transfer （LICET） process. The spectrum of laser-induced quadrupole quadrupole collisional energy transfer in Xe-Kr system has wider tunable range in an order of magnitude than the dipole-dipole LICET spectra. The peak cross section decreases and moves to the quasi-static wing with increasing temperature and the full width at half peak of the profile becomes larger as the system temperature increases.
文摘A four-state model considering the relative velocity distribution function for calculating the cross section of laserinduced collisional energy transfer in a Sr Li system is presented and profiles of laser-induced collision cross section are obtained. The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry. Both of the two intermediate states have contributions to the final state, and none of the intermediate states should be neglected. The peak of the laser-induced collisional energy transfer （LICET） profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing. A cross section of 1.2 × 10^-12 cm2 at a laser field intensity of 2.17 ×107 V/m is obtained, which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state. The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process, which is not accounted for in a two-state treatment.
