Absolute measurement of state-resolved charge-exchange cross sections for mathrm C ^4^+ colliding with mathrm H _2

Solar wind interaction with planetary atmosphere and cometary coma is a fundamental process for space weather studies. Observations of extremely ultraviolet and soft X-ray emissions are generally attributed to charge exchange between highly charged ions and neutral atoms. To understand the emission spectra, reliable cross sections are required, particularly those resolved with respect to the principal quantum number and orbital angular momentum quantum number of the captured electron. n l This work aims to measure absolute -resolved charge-exchange (CX) cross sections for mathrm nl C ^4^+ colliding with mathrm H _2 at solar wind velocities, providing experimental benchmarks for theoretical calculations and accurate atomic data to support astrophysical EUV spectral simulations of solar wind CX emission. The experiments were conducted based on the 150 kV highly charged ion platform at Fudan University. The total and state-selective cross sections were measured using beam-gas collisions in conjunction with cold-target recoil-ion momentum spectroscopy. We present absolute total cross sections for single electron capture (SEC) and double electron capture (DEC), as well as -resolved cross sections for SEC in mathrm nl C ^4^++mathrm H _2. The collision energy ranges from 2.3 to 33.3 keV/u, corresponding to velocities of 671 - 2535 km/s. The cross sections are determined with uncertainties of 9% for SEC and 10% for DEC, respectively. The experiments extend CX cross section data to higher collision energies and reveal contributions from electron capture into high- states. These results are not predicted by the existing theories. n This study presents experimentally determined -resolved CX cross sections for the mathrm nl C ^4^++mathrm H _2 system, covering the collision energy range relevant to the solar wind. These results serve as a benchmark for testing theoretical calculations and support the modeling of CX-induced astrophysical emissions.