8 research outputs found

    Generalized photon-added associated hypergeometric coherent states: characterization and relevant properties

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    This paper presents the construction of a new set of generalized photon-added coherent states related to associated hypergeometric functions introduced in our previous work (Hounkonnou M N and Sodoga K, 2005, J. Phys. A: Math. Gen 38, 7851). These states satisfy all required mathematical and physical properties. The associated Stieltjes power-moment problem is explicitly solved by using Meijer's G-function and the Mellin inversion theorem. Relevant quantum optical and thermal characteristics are investigated. The formalism is applied to particular cases of the associated Hermite, Laguerre, Jacobi polynomials and hypergeometric functions. Their corresponding states exhibit sub-Poissonian photon number statistics

    Ab initio calculation of H + He+^+ charge transfer cross sections for plasma physics

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    The charge transfer in low energy (0.25 to 150 eV/amu) H(nlnl) + He+(1s)^+(1s) collisions is investigated using a quasi-molecular approach for the n=2,3n=2,3 as well as the first two n=4n=4 singlet states. The diabatic potential energy curves of the HeH+^+ molecular ion are obtained from the adiabatic potential energy curves and the non-adiabatic radial coupling matrix elements using a two-by-two diabatization method, and a time-dependent wave-packet approach is used to calculate the state-to-state cross sections. We find a strong dependence of the charge transfer cross section in the principal and orbital quantum numbers nn and ll of the initial or final state. We estimate the effect of the non-adiabatic rotational couplings, which is found to be important even at energies below 1 eV/amu. However, the effect is small on the total cross sections at energies below 10 eV/amu. We observe that to calculate charge transfer cross sections in a nn manifold, it is only necessary to include states with nnn^{\prime}\leq n, and we discuss the limitations of our approach as the number of states increases.Comment: 14 pages, 10 figure

    Ab initio calculation of the 66 low lying electronic states of HeH+^+: adiabatic and diabatic representations

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    We present an ab initio study of the HeH+^+ molecule. Using the quantum chemistry package MOLPRO and a large adapted basis set, we have calculated the adiabatic potential energy curves of the first 20 1Σ+^1 \Sigma^+, 19 3Σ+^3\Sigma^+, 12 1Π^1\Pi, 9 3Π^3\Pi, 4 1Δ^1\Delta and 2 3Δ^3\Delta electronic states of the ion in CASSCF and CI approaches. The results are compared with previous works. The radial and rotational non-adiabatic coupling matrix elements as well as the dipole moments are also calculated. The asymptotic behaviour of the potential energy curves and of the various couplings between the states is also studied. Using the radial couplings, the diabatic representation is defined and we present an example of our diabatization procedure on the 1Σ+^1\Sigma^+ states.Comment: v2. Minor text changes. 28 pages, 18 figures. accepted in J. Phys.

    Photodissociation and radiative association of HeH+ in the metastable triplet state

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    We investigate the photodissociation of the metastable triplet state of HeH+ as well as its formation through the inverse process, radiative association. In models of astrophysical plasmas, HeH+ is assumed to be present only in the ground state, and the influence of the triplet state has not been explored. It may be formed by radiative association during collisions between a proton and metastable helium, which are present in significant concentrations in nebulae. The triplet state can also be formed by association of He+ and H, although this process is less likely to occur. We compute the cross sections and rate coefficients corresponding to the photodissociation of the triplet state by UV photons from a central star using a wave packet method. We show that the photodissociation cross sections depend strongly on the initial vibrational state and that the effects of excited electronic states and non-adiabatic couplings cannot be neglected. We then calculate the cross section and rate coefficient for the radiative association of HeH+ in the metastable triplet state.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Caring about microenvironments

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