The role of asymptotic vibrational states in

2006 ◽  
Vol 364 (1848) ◽  
pp. 2903-2916 ◽  
Author(s):  
Jonathan Tennyson ◽  
Paolo Barletta ◽  
James J Munro ◽  
Bruno C Silva
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Bound States ◽  
Energy Surface ◽  
Graphical Analysis ◽  
Molecular Ions ◽  
Feshbach Resonances ◽  
Vibrational States ◽  
Photodissociation Spectrum

Calculations are discussed which characterize all the vibrational bound states of the and D 2 H + molecular ions using a realistic ab initio potential energy surface. Graphical analysis and calculation of rotational constants show that both ions support a series of atom–diatom-like long-range states: asymptotic vibrational states. The role of these states in the system and other molecules is discussed. The vibrational calculations are extended above dissociation where the resulting (Feshbach) resonances are shown to be too short-lived to be of importance for the photodissociation spectrum.

scholarly journals Photodissociation as a probe of the H 3 + avoided crossing seam

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180399 ◽  
Author(s):  
X. Urbain ◽  
A. Dochain ◽  
R. Marion ◽  
T. Launoy ◽  
J. Loreau
Keyword(s):  
Charge Transfer ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Branching Ratio ◽  
Kinetic Energy Release ◽  
Molecular Ions ◽  
Near Ultraviolet ◽  
Avoided Crossing

Experiments are conducted to investigate the role of the avoided crossing seam in the photodissociation of H 3 + . Three-dimensional imaging of dissociation products is used to determine the kinetic energy release and branching ratio among the fragmentation channels. Vibrational distributions are measured by dissociative charge transfer of H 2 + products. It is found that the photodissociation of hot H 3 + in the near-ultraviolet produces cold H 2 + , but hot H 2 . Modelling the wavepacket dynamics along the repulsive potential energy surface accounts for the repopulation of the ground potential energy surface. The role of the avoided crossing seam is emphasized and its importance for the astrophysically relevant charge transfer reactions underlined. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Rotational de-excitations of C3H+ (1Σ+) by collision with He: new ab initio potential energy surface and scattering calculations

2020 ◽  
Vol 494 (4) ◽  
pp. 5675-5681 ◽  
Author(s):  
Sanchit Chhabra ◽  
T J Dhilip Kumar
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Cross Sections ◽  
Energy Surface ◽  
Molecular Ions ◽  
Basis Set ◽  
Rate Coefficients ◽  
Close Coupling ◽  
Collisional Rate Coefficients

ABSTRACT Molecular ions play an important role in the astrochemistry of interstellar and circumstellar media. C3H+ has been identified in the interstellar medium recently. A new potential energy surface of the C3H+–He van der Waals complex is computed using the ab initio explicitly correlated coupled cluster with the single, double and perturbative triple excitation [CCSD(T)-F12] method and the augmented correlation consistent polarized valence triple zeta (aug-cc-pVTZ) basis set. The potential presents a well of 174.6 cm−1 in linear geometry towards the H end. Calculations of pure rotational excitation cross-sections of C3H+ by He are carried out using the exact quantum mechanical close-coupling approach. Cross-sections for transitions among the rotational levels of C3H+ are computed for energies up to 600 cm−1. The cross-sections are used to obtain the collisional rate coefficients for temperatures T ≤ 100 K. Along with laboratory experiments, the results obtained in this work may be very useful for astrophysical applications to understand hydrocarbon chemistry.

scholarly journals Progress in calculating the potential energy surface of H 3 +

2012 ◽  
Vol 370 (1978) ◽  
pp. 5001-5013 ◽  
Author(s):  
Ludwik Adamowicz ◽  
Michele Pavanello
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Molecular Geometry ◽  
Computational Procedure ◽  
Energy Functional ◽  
Basis Functions ◽  
Vibrational States ◽  
Energy Gradient ◽  
Explicitly Correlated

The most accurate electronic structure calculations are performed using wave function expansions in terms of basis functions explicitly dependent on the inter-electron distances. In our recent work, we use such basis functions to calculate a highly accurate potential energy surface (PES) for the H ion. The functions are explicitly correlated Gaussians, which include inter-electron distances in the exponent. Key to obtaining the high accuracy in the calculations has been the use of the analytical energy gradient determined with respect to the Gaussian exponential parameters in the minimization of the Rayleigh–Ritz variational energy functional. The effective elimination of linear dependences between the basis functions and the automatic adjustment of the positions of the Gaussian centres to the changing molecular geometry of the system are the keys to the success of the computational procedure. After adiabatic and relativistic corrections are added to the PES and with an effective accounting of the non-adiabatic effects in the calculation of the rotational/vibrational states, the experimental H rovibrational spectrum is reproduced at the 0.1 cm −1 accuracy level up to 16 600 cm −1 above the ground state.

Theoretical Studies of Potential Energy Surface and Bound States of the Strongly Bound He(1S)–BeO (1Σ+) Complex

2013 ◽  
Vol 117 (30) ◽  
pp. 6657-6663 ◽  
Author(s):  
Michał Hapka ◽  
Jacek Kłos ◽  
Tatiana Korona ◽  
Grzegorz Chałasiński
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Bound States ◽  
Energy Surface ◽  
Theoretical Studies

Rovibrational energy transfer in the He-C3 collision: Potential energy surface and bound states

2014 ◽  
Vol 140 (8) ◽  
pp. 084316 ◽  
Author(s):  
Otoniel Denis-Alpizar ◽  
Thierry Stoecklin ◽  
Philippe Halvick
Keyword(s):  
Energy Transfer ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Bound States ◽  
Energy Surface

Rotational spectrum, potential energy surface, and bound states of the weakly bound complex He–N[sub 2]O

2004 ◽  
Vol 121 (24) ◽  
pp. 12308 ◽  
Author(s):  
XiaoGeng Song ◽  
Yunjie Xu ◽  
Pierre-Nicholas Roy ◽  
Wolfgang Jäger
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Bound States ◽  
Energy Surface ◽  
Rotational Spectrum ◽  
Weakly Bound
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