35 / 2026-03-07 15:45:51

Charge exchange processes in low-energy collisions of C3+ ions with H and D

Charge exchange,oscillatory structures,multi-channel interference,spin-statistics rule

极端条件下的基础物理 > 极端条件下的原子物理、核物理与等离子体物理

Charge exchange processes in collisions of C³⁺(1s²2s ²S) ions with hydrogen and deuterium atoms are investigated employing the full quantum-mechanical molecular-orbital close-coupling (QMOCC) method in the large energy range of 10^-5-10 keV/u. The required molecular potential curves and coupling matrix elements are calculated with full active electrons by the ab initio multireference single- and double-excitation configuration interaction (MRD-CI) method, and large basis sets are employed to obtain accurate asymptotic energy differences. Total and state-selective electron capture cross sections and rate coefficients are obtained and show satisfactory agreement with the experimental data. It is found that the total cross sections increase as the collision energy decreases with the dominance of 2s3s ³S and 2p^2 1S channels in the energy region below 0.1 keV/u, and then increase as the collision energy increases above 0.1 keV/u due to the contributions of higher states. Meanwhile, the total cross sections exhibit complex oscillatory behaviors in various energy regions. Below 1 eV/u, the dense oscillatory structures arise from quasi-bound vibrotational states in the entrance channel, and the isotope effect for hydrogen and deuterium targets is noticeable in this energy region.  Around 10 eV/u, the oscillatory patterns originate from the interference between the 2p^2 1S channel and the entrance channel, while in the 0.5-3.0 keV/u energy range, the oscillatory structures primarily arise from the multi-channel interference among the 2s3s, 2s3p, 2p3s and 2s4s states in both the triplet and singlet states of C²⁺ ions. The ratios of cross sections for electron capture to the triplet and singlet state manifolds are found to deviate from the spin-statistics rule because of the significant differences in electron capture to 2p² and 2s3s electronic configurations between triplet and singlet states.