Hiroya Suno

Adiabatic hyperspherical study of triatomic helium systems

The 4 He3 system is studied using the adiabatic hyperspherical representation. We adopt the current state-of-the-art helium interaction potential including retardation and the nonadditive three-body term, to calculate all low-energy properties of the triatomic 4 He system. The bound state energies of the 4 He trimer are computed as well as the 4 He+ 4 He2 elastic scattering cross sections, the three-body recombination and collision induced dissociation rates at finite temperatures. We also treat the system that consists of two 4 He and one 3 He atoms, and compute the spectrum of the isotopic trimer 4 He2 3 He, the 3 He+ 4 He2 elastic scattering cross sections, the rates for three-body recombination and the collision induced dissociation rate at finite temperatures. The effects of retardation and the nonadditive three-body term are investigated. Retardation is found to be significant in some cases, while the three-body term plays only a minor role for these systems.

A theoretical study of Ne3 using hyperspherical coordinates and a slow variable discretization approach.

We study theoretically the ground and excited bound states of the bosonic rare gas van der Waals trimer Ne(3). A slow variable discretization approach is adopted to solve the nuclear Schrödinger equation, in which the Schrödinger equation in hyperangular coordinates is solved using basis splines at a series of fixed finite-element methods discrete variable representation hyper-radii. We consider not only zero total nuclear orbital angular momentum, J = 0, states but also J > 0 states. By using the best empirical neon dimer interaction potentials, all the bound state energy levels of Ne(3) will be calculated for total angular momenta up to J = 6, as well as their average root-mean-square radii. We also analyze the wave functions in hyperspherical coordinates for several selected bound states.

Hyperspherical slow variable discretization method for weakly bound triatomic molecules

We develop a method for calculating the bound state energies and the wave functions of weakly bound triatomic molecular systems. The method is based on the use of hyperspherical coordinates, combined with the slow variable discretization approach. The finite-element methods-discrete variable representation scheme provides an efficient means to solve the coupled-channel hyper-radial equations. Our method is applied to searching for bound states of the (20)Ne(2)H and (4)He(20)NeH triatomic molecules, using the best empirical pairwise interaction potentials. We consider not only zero total nuclear orbital momentum, J = 0, states but also J > 0 states. The (20)Ne(2)H system has been found to possess one bound state each for the J(Π)=0(+),1(-), and 2(+) symmetries, while there exist only one bound state for the (4)He(20)NeH system in the 0(+) symmetry. We shall calculate the bound state energies and analyze the molecular structures of these species in detail.

Adiabatic hyperspherical study of weakly bound He2H−, He2H, and HeH2 systems

The He(2)H(-), He(2)H, and HeH(2) triatomic systems are studied using the adiabatic hyperspherical representation. By adopting the best empirical interaction potentials, we search for weakly bound states of (4)He(2) H(-), (4)He(2) H, and (4)HeH(2). We consider not only zero total nuclear orbital angular momentum, J=0, states but also J>0 states. We find no bound state for the (4)He(2) H systems, while the (4)He(2) H(-) and (4)HeH(2) systems are shown to possess three and one bound states, respectively, for J(Pi)=0(+). Interestingly, one bound state has been found each for the J(Pi)=1(-) and 2(+) symmetries of the (4)He(2) H(-) anion. We shall calculate the bound state energies and analyze the molecular structure of these species in detail.

Charge Transfer Processes in Ion‐Molecule Collisions at Intermediate Energies; the Vibrational Effect, Isotope Effect, Isomer Effect, and Steric Effect

Charge transfer processes resulting from collisions of H+ ions with H2, HD, D2, CH2, CH4, C2H2, C2H4 and C2H6 molecules have been investigated in the energy range of 0.2 to 10.0 keV by using experimental as well as theoretical approaches. The initial growth rate method was employed for the experimental study of the dynamics and cross sections, while theoretical analysis based on a molecular‐orbital expansion method for all these targets was carried out. The present results for the H2, HD and D2 molecules are found be in excellent accord with most of previous measurements above 1 keV and to show a conspicuous isotope effect, that is, the cross sections for three molecules differs in sizable amounts particularly below a few keV. For CmHn hydrocarbon targets (m ⩽ 3), both experimental and theoretical results indicate that if the target is in a vibrationally excited state, then charge transfer processes sometimes become more favorable since these vibrationally excited states enforce an accidental resonant con...