Experimental Study On State-selective Charge Transfer Between Low-energy Neon Ion And He/H₂ Target

Charge exchange between highly charged ions and neutral atoms and molecules has been considered as one of important mechanisms controlling soft X-ray emissions in many astrophysical objects and environments.Whereas for modelling charge exchange soft X-ray emission these data of principal quantum numbernand angular quantum numberl-resolved state-selective capture cross-sections are often obtained by empirical and semi-classical theoretical calculations.With a newly-built cold target recoil ion mo-mentum spectroscopy（COLTRIMS）apparatus,we perform a series of measurements on charge exchange process of Ne⁽（8,n+）ions with He and H₂ for the collision energy ranging from 1 to 24.75 ke V/u.n-resolved state-selective capture cross-sections are reported.For the Ne⁸⁺-He and H₂ collision system,state-selective cross-sections and angu-lar differential cross-section are o btained.By comparing the measured state-selective cross-sectionss to these calculated by the multichannel Landau-Zener method（MCLZ）and the molecular Coulomb over barrier model（MCBM）,it is found that MCLZ and MCBM calculations are in good agreement with the measurements for the dominantncapture for He target.Furthermore,by usingnl-resolved cross-sections calculated by MCLZ and applyingldistributions commonly-used in astrophysical literatures to ex-perimentally derivedn-resolved cross-sections,we calculate the soft X-ray emissions in the charge exchange of 1.6,2.4 and 4 ke V/u Ne⁸⁺-He by considering the radiative cas-cade from the excited Ne⁷⁺ion.Reasonable agreement is found in comparison between the measurement and the even and separable models.For the two-electron transfer pro-cess of Ne⁸⁺-He,the double-excited state of the two-electron capture population was successfully identified,and the angular differential cross-sections of the population of different states were obtained.Secondly,we systematically reported for the first time the single electron trans-fer process between Ne⁹⁺-He and H₂ targets at a collision energy of 2.25 ke V/u-24.75ke V/u,obtained the Q value spectrum and the angular differential cross-section,and studied the collision dynamics of single electron capture.The experimental results are compared with those calculated by the TC-AOCC method.In terms of the state-selective cross-sections,the main state population reaction channel is consistent with the prediction of AOCC,and there is a big difference in small contribution channels between experimental measurement and the AOCC prediction.In terms of angular dif-ferential cross-section,AOCC predicts the angular distribution of the individual cap-ture channel well.Furemore,the two-electron transfer process between Ne⁹⁺-He was measured,the Q value spectrum and the total scattering angle distribution of the two-electron transfer were obtained,and the quantum state population of the two-electron transfer process was determined.