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’.

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.

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.

Dissection of the multichannel reaction of acetylene with atomic oxygen: from the global potential energy surface to rate coefficients and branching dynamics

2019 ◽  
Vol 21 (3) ◽  
pp. 1408-1416 ◽  
Author(s):  
Junxiang Zuo ◽  
Qixin Chen ◽  
Xixi Hu ◽  
Hua Guo ◽  
Daiqian Xie
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Atomic Oxygen ◽  
Energy Surface ◽  
Rate Coefficient ◽  
Branching Ratio ◽  
Classical Trajectory ◽  
Rate Coefficients ◽  
Product Branching

A global potential energy surface for the O(3P) + C2H2reaction is developed and the quasi-classical trajectory study on the potential energy surface reproduce the rate coefficient and product branching ratio.

scholarly journals Non-adiabatic effects in the H 3 + spectrum

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180411 ◽  
Author(s):  
Paulo H. R. Amaral ◽  
Monika Stanke ◽  
Ludwik Adamowicz ◽  
Leonardo G. Diniz ◽  
José R. Mohallem ◽  
...  
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Quantum Electrodynamic ◽  
Energy Surface ◽  
Energy Levels ◽  
High Accuracy ◽  
Empirical Method ◽  
Molecular Ions ◽  
Stockholder Atoms ◽  
Existing Data

The effect of non-adiabatic coupling on the computed rovibrational energy levels amounts to about 2 cm −1 for H 3 + and must be included in high-accuracy calculations. Different strategies to obtain the corresponding energy shifts are reviewed in the article. A promising way is to introduce effective vibrational reduced masses that depend on the nuclear configuration. A new empirical method that uses the stockholder atoms-in-molecules approach to this effect is presented and applied to H 3 + . Furthermore, a highly accurate potential energy surface for the D 3 + isotopologue, which includes relativistic and leading quantum electrodynamic terms, is constructed and used to analyse the observed rovibrational frequencies for this molecule. Accurate band origins are obtained that improve existing data. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Dramatic changes in the excited-state behaviour of the green fluorescent protein chromophore by a strong π-donating group through significantly lowering the excited-state potential energy surface with photoinduced intramolecular charge transfer

2020 ◽  
Vol 22 (4) ◽  
pp. 2424-2428
Author(s):  
Yi-Hui Chen ◽  
Robert Sung ◽  
Kuangsen Sung
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Green Fluorescent Protein ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Fluorescent Protein ◽  
Intramolecular Charge Transfer ◽  
State Potential ◽  
Green Fluorescent

A strong π-donating group like p-NMe2 significantly lowers the S1 excited-state potential energy surface of green fluorescent protein chromophore by photoinduced intramolecular charge transfer, dramatically changing its excited-state behavior.

scholarly journals Secondary channels in the thermal decomposition of monomethylhydrazine (CH3NHNH2)

RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 62951-62964 ◽  
Author(s):  
Peng Zhang ◽  
Stephen J. Klippenstein ◽  
Lawrence B. Harding ◽  
Hongyan Sun ◽  
Chung K. Law
Keyword(s):  
Thermal Decomposition ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Molecular Decomposition

The possible role of molecular decomposition channels in MMH is explored through additional investigations on triplet channels, roaming radical channels, and previously unexplored pathways on the potential energy surface.

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