The global ground and first three excited electronic state adiabatic as well as the corresponding quasidiabatic potential energy surfaces is reported as a function of nuclear geometries in the Jacobi coordinates (R →, r →, γ) using Dunning's cc-pVTZ basis set at the internally contracted multi-reference (single and double) configuration interaction level of accuracy. Nonadiabatic couplings, arising out of relative motion of proton and the vibrational motion of CO, are also reported in terms of coupling potentials. The quasidiabatic potential energy surfaces and the coupling potentials have been obtained using the ab initio procedure [Simah et al., J. Chem. Phys. 111, 4523 (1999)] for the purpose of dynamics studies. © 2016 AIP Publishing LLC.

Velluvakandi Chaluvalappil Saheer

Electronic states

Excited states

Molecular physics

Potential energy surfaces

Quantum chemistry

AB INITIO PROCEDURES

Configuration interactions

Dynamics studies

EXCITED ELECTRONIC STATE

JACOBI COORDINATES

NON-ADIABATIC COUPLING

NUCLEAR GEOMETRY

VIBRATIONAL MOTIONS

Potential energy

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IIT Madras

Ab initio adiabatic and quasidiabatic potential energy surfaces of H+ + CO system: A study of the ground and the first three excited electronic states

Journal of Chemical Physics

An ab initio full configuration interaction study has been undertaken to obtain the global potential energy surfaces for the ground and the first excited electronic state of the H+ + H2 system employing Dunning's cc-pVQZ basis set. Using the ab initio approach the corresponding quasi-diabatic potential energy surfaces and coupling potentials have been obtained. A time-independent quantum mechanical study has been also undertaken for both the inelastic and charge transfer processes at the experimental collision energy Ec.m. = 20.0 eV and the preliminary results show better agreement with the experimental data as compared to the earlier available theoretical studies. © 2007 Elsevier B.V. All rights reserved.

Chemical Physics Letters

Ab initio study of H+ + H2 collisions: Elastic/inelastic and charge transfer processes

Proton and hydrogen atom time-of-flight spectra in collision energy range of Etrans =9.5-30 eV show that the endoergic charge transfer process in the H+ +CO system is almost an order of magnitude less probable than the elastic scattering [G. Niedner-Schatteburg and J. P. Toennies, Adv. Chem. Phys. LXXXII, 553 (1992)]. Ab initio computations at the multireference configuration interaction level have been performed to obtain the ground- and several low-lying excited electronic state potential energy curves in three different molecular orientations namely, H+ approaching the O-end and the C-end (collinear), and H+ approaching the CO molecule in perpendicular configuration with fixed CO internuclear distance. Nonadiabatic coupling terms between the ground electronic state (H+ +CO) and the three low-lying excited electronic states (H+ CO+) have been computed and the corresponding diabatic potentials have been obtained. A time-dependent wavepacket dynamics study is modeled first involving only the ground and the first excited states and then involving the ground and the three lowest excited states at the collision energy of 9.5 eV. The overall charge transfer probability have been found to be ≈20%-30% which is in qualitative agreement with the experimental findings. © 2006 American Institute of Physics.

Fulltext

Elastic and charge transfer processes in H + +CO collisions

Wiley Interdisciplinary Reviews: Computational Molecular Science

Molpro: a general-purpose quantum chemistry program package

The quantum mechanical state-to-state rotational excitation cross sections have been computed using the ab initio ground electronic state potential energy surface of the system [M. Mladenovic and S. Schmatz, J. Chem. Phys. 109, 4456 (1998)] computed at coupled-cluster single and double and triple perturbative excitations method using correlation-consistent polarized valence quadruple zeta basis set where the asymptotic potential have been computed using the dipole moment, quadrupole moment, and the molecular polarizability components and fitted to this interaction potential. The anisotropy of the surface has been analyzed in terms of the multipolar expansion coefficients for the rigid-rotor surface. The integral cross sections for rotational excitations have been computed by solving close-coupled equations at very low collision energies (5-200 cm -1) and the corresponding rates have been obtained for a range of low temperatures (5-175 K). The j = 0 → j ′ 1 rotational excitation cross section (and rate) is found to be the dominant followed by the j 0 → j ′ 2 in these collision energies. The close-coupling, coupled-state, and infinite-order sudden approximations coupling calculations have been performed in the energy range of 0.1-1.0 eV using vibrational ground potential. The rotational cross sections have been obtained by performing computationally accurate close-coupling calculations at 0.1 eV using vibrationally averaged potential (v 1) and compared with the results of vibrational ground potential. © 2012 American Institute of Physics.

Low-energy rotational inelastic collisions of H + + CO system

The vibrational mode-selective scattering properties have been computed for the H++CO system at two experimentally reported collision energies, Ec.m.=9.5 eV and Ec.m.=28.96 eV, for elastic, inelastic, and charge-transfer channels, using the vibrational close-coupling rotationally infinite-order sudden approximation (VCC-RIOSA) scheme, making use of the ab initio potentials of the ground-state (GS) and the first-excited-state (ES) potential energy surfaces (PESs) of the bound HCO+ molecule computed at the multireference configuration interaction (MRCI) level of accuracy and using the cc-pVTZ basis set in Jacobi coordinates (R,r,γ). The vibronic couplings used as input in computing the scattering quantities were computed and compared with previously reported couplings to give a fair idea about the extent of deviation from the present work. The scattering quantities are compared with the available experimental results and the computed data are found to match the experimental results even though there are noteworthy disagreements. © 2011 American Physical Society.

Physical Review A - Atomic, Molecular, and Optical Physics

Quantum dynamics of H++CO collisions

Journal	Data powered by TypesetJournal of Chemical Physics
Publisher	Data powered by TypesetAmerican Institute of Physics Inc.
ISSN	00219606
Open Access	No