State-selective electron capture cross sections in collision between fully striped ions and ground state hydrogen atom—Classical treatment of the collision

Testing standard basis sets for direct ionizations: H+ + H at ELab = 0.1–100 keV

“…The MAPEs of total CT, total DI, and 1s à 2s TE integral cross-sections of H + + H from SLEND calculations with various basis sets and with respect to their experimental counterparts by McClure 43 (CT), Shah et al [44][45][46] (DI), and Higgins et al 47 number of considered ICSs values (sample size). In addition, Table 3 presents the ICSs MAPEs of the same three processes from SLEND and from alternative theoretical methods: TC-BGM by Leung and Kirchner, 12 OCC-CC by Abdurakhmanov et al, 11 FODWT by Das et al, 15 and CTMC and QCTMC by Ziaeian and T} okési, 14 all with respect to the aforesaid experimental data. [43][44][45][46][47] In Table 3, we report the lowest SLEND ICSs MAPEs per process and energy range; these MAPEs correspond to the most accurate SLEND calculations and are identified by the utilized basis set.…”

“…We consider low and high energy ranges (in addition to the full one) because some sets of experimental data lie entirely in either of them. Finally, Figures 4-6 plot the best SLEND ICSs values for the total CT (SLEND/aug-cc-pVTZ), total DI (SLEND/aug-cc-pVDZ and /q-aug-cc-pVDZ) and 1s à 2s TE (SLEND/6-311++G**) processes, respectively, versus the collision energy E Lab and along with their counterparts from the theoretical methods considered in Table 3 11,12,14,15 and from numerous experiments. [43][44][45][46][47] Before proceeding to analyze the obtained SLEND ICSs, we should point out once again that the tested STO/CGFs basis sets were originally designed for the time-independent prediction of bound-state molecular properties, and not for the time-dependent simulation of electronic processes; this is particularly the case for the demanding DI processes involving unbound states.…”

“…The MAPEs of total CT, total DI, and 1s à 2s TE integral cross-sections (ICSs) of H + + H from various theoretical methods: TC-BGM by Leung and Kirchner, 12 OCC-CC by Abdurakhmanov et al, 11 FODWT by Das et al, 15 CTMC and QCTMC by Ziaeian and T} okési, 14 and SLEND, with respect to their experimental counterparts by McClure 43 (CT), Shah et al [44][45][46] (DI), and Higgins et al 47 (TE).…”

“…In the field of molecular physics, simulations of ion-molecule reactions mostly concentrated on electronic processes (CTs, DIs, and TEs), with little consideration, if not neglect, of nuclear processes (fragmentations, rearrangements, substitutions, etc.). [5][6][7][8][9][10][11][12][13][14][15] To treat electronic processes, numerous and diverse methods have been developed, such as the numerical solution of the time-dependent Schrödinger equation on a lattice, 5 the numerical solution of the time-dependent two-center Dirac equation with Dirac-Sturm basis functions, 6 various versions of the quantum close-coupling (CC) method [e.g., two-center atomic orbital CC (TCAO-CC), 7 molecular orbital (MO) CC (MO-CC), 8 semiclassical-atomic orbital CC (SC-AO-CC), 9 quantum mechanical convergent (QMC) CC (QMC-CC), 10 and one-center convergent (OCC) CC (OCC-CC) 11 ], the two-center basis generator method (TC-BGM), 12 the continuum distorted wave scattering method, 13 the first-order distorted wave theory (FODWT), 15 and classical and quasi-classical trajectory Monte Carlo methods (CTMC and QTMC, respectively). 9,14 These methods provided valuable insight into the investigated processes and predicted accurate properties.…”

“…[5][6][7][8][9][10][11][12][13][14][15] To treat electronic processes, numerous and diverse methods have been developed, such as the numerical solution of the time-dependent Schrödinger equation on a lattice, 5 the numerical solution of the time-dependent two-center Dirac equation with Dirac-Sturm basis functions, 6 various versions of the quantum close-coupling (CC) method [e.g., two-center atomic orbital CC (TCAO-CC), 7 molecular orbital (MO) CC (MO-CC), 8 semiclassical-atomic orbital CC (SC-AO-CC), 9 quantum mechanical convergent (QMC) CC (QMC-CC), 10 and one-center convergent (OCC) CC (OCC-CC) 11 ], the two-center basis generator method (TC-BGM), 12 the continuum distorted wave scattering method, 13 the first-order distorted wave theory (FODWT), 15 and classical and quasi-classical trajectory Monte Carlo methods (CTMC and QTMC, respectively). 9,14 These methods provided valuable insight into the investigated processes and predicted accurate properties. However, their way of representing the continuous and unbound states of electrons involved in DIs remains rather alien to quantum chemistry praxis (e.g., representations via numerical lattices 5 and distorted scattering waves 13 ).…”