We studied the excitation spectra in the case of Xe@(p-H2)n embedded in a solid-state parahydrogen, making use of the ab initio molecular orbital method (QMO), in order to seek the possibility of the radiative emissio...We studied the excitation spectra in the case of Xe@(p-H2)n embedded in a solid-state parahydrogen, making use of the ab initio molecular orbital method (QMO), in order to seek the possibility of the radiative emission of the neutrino pair (RENP) process that may be associated with the E1 × M1 transition processes. By means of a QMO calculation, the remarkable matrix effect was found in the structure of the electronic states. Three E1-type excitation bands (ε1, ε2, ε3, in the order of increasing energy) in the UV absorption were found. In the present preliminary calculation, the second was too close to be clearly/well distinguished as an independent peak observed in the last experiment. Nevertheless, across the second (ε2) band, two associated bands that may link to the M1-type transition were found. Therefore, the M1-type de-excitation process may be probable with the help of intensity borrowing from the ε2 band, which may support the probability of the RENP process.展开更多
The single-and double-electron capture(SEC, DEC) processes of He^(2+) ions colliding with Ne atoms are studied by utilizing the full quantum-mechanical molecular-orbital close-coupling method. Total and state-selectiv...The single-and double-electron capture(SEC, DEC) processes of He^(2+) ions colliding with Ne atoms are studied by utilizing the full quantum-mechanical molecular-orbital close-coupling method. Total and state-selective SEC and DEC cross sections are presented in the energy region of 2 eV/u to 20 keV/u. Results show that the dominant reaction channel is Ne^(+)(2s2p^(6) ^(2)S) + He^(+)(1s) in the considered energy region due to strong couplings with the initial state Ne(2s^(2)2p^(6)^(1)S) + He^(2+) around the internuclear distance of 4.6 a.u. In our calculations, the SEC cross sections decrease initially and then increase whereby, the minimum point is around 0.38 keV/u with the increase of collision energies. After considering the effects of the electron translation factor(ETF), the SEC cross sections are increased by 15%–25% nearby the energy region of keV/u and agree better with the available results. The DEC cross sections are smaller than those of SEC because of the larger energy gaps and no strong couplings with the initial state. Due to the Demkov-type couplings between DEC channel Ne^(2+)(2s^(2)2p^(4)^(1)S) + He(1s^(2)) and the dominating SEC channel Ne^(+)(2s2p^(6) ^(2)S) + He^(+)(1s), the DEC cross sections increase with increasing impact energies. Good consistency can also be found between the present DEC and the experimental measurements in the overlapping energy region.展开更多
文摘We studied the excitation spectra in the case of Xe@(p-H2)n embedded in a solid-state parahydrogen, making use of the ab initio molecular orbital method (QMO), in order to seek the possibility of the radiative emission of the neutrino pair (RENP) process that may be associated with the E1 × M1 transition processes. By means of a QMO calculation, the remarkable matrix effect was found in the structure of the electronic states. Three E1-type excitation bands (ε1, ε2, ε3, in the order of increasing energy) in the UV absorption were found. In the present preliminary calculation, the second was too close to be clearly/well distinguished as an independent peak observed in the last experiment. Nevertheless, across the second (ε2) band, two associated bands that may link to the M1-type transition were found. Therefore, the M1-type de-excitation process may be probable with the help of intensity borrowing from the ε2 band, which may support the probability of the RENP process.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 11774344 and 11474033)the National Key Research and Development Program of China (Grant No. 2017YFA0402300)。
文摘The single-and double-electron capture(SEC, DEC) processes of He^(2+) ions colliding with Ne atoms are studied by utilizing the full quantum-mechanical molecular-orbital close-coupling method. Total and state-selective SEC and DEC cross sections are presented in the energy region of 2 eV/u to 20 keV/u. Results show that the dominant reaction channel is Ne^(+)(2s2p^(6) ^(2)S) + He^(+)(1s) in the considered energy region due to strong couplings with the initial state Ne(2s^(2)2p^(6)^(1)S) + He^(2+) around the internuclear distance of 4.6 a.u. In our calculations, the SEC cross sections decrease initially and then increase whereby, the minimum point is around 0.38 keV/u with the increase of collision energies. After considering the effects of the electron translation factor(ETF), the SEC cross sections are increased by 15%–25% nearby the energy region of keV/u and agree better with the available results. The DEC cross sections are smaller than those of SEC because of the larger energy gaps and no strong couplings with the initial state. Due to the Demkov-type couplings between DEC channel Ne^(2+)(2s^(2)2p^(4)^(1)S) + He(1s^(2)) and the dominating SEC channel Ne^(+)(2s2p^(6) ^(2)S) + He^(+)(1s), the DEC cross sections increase with increasing impact energies. Good consistency can also be found between the present DEC and the experimental measurements in the overlapping energy region.
