scholarly journals A new (multi-reference configuration interaction) potential energy surface for H 2 CO and preliminary studies of roaming

2017 ◽  
Vol 375 (2092) ◽  
pp. 20160194 ◽  
Author(s):  
Xiaohong Wang ◽  
Paul L. Houston ◽  
Joel M. Bowman
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Global Minimum ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Classical Trajectory ◽  
Statistical Dynamics ◽  
Trajectory Calculations ◽  
Switching Functions ◽  
Interaction Potential Energy

We report a new global potential energy surface (PES) for H 2 CO, based on precise fitting of roughly 67 000 MRCI/cc-pVTZ energies. This PES describes the global minimum, the cis - and trans -HCOH isomers, and barriers relevant to isomerization, formation of the molecular (H 2 +CO) and radical (H+HCO) products, and the loose so-called roaming transition-state saddle point. The key features of the PES are reviewed and compared with a previous PES, denoted by PES04, based on five local fits that are ‘stitched’ together by switching functions (Zhang et al. 2004 J. Phys. Chem. A 108 , 8980–8986 ( doi:10.1021/jp048339l )). Preliminary quasi-classical trajectory calculations are performed at the total energy of 36 233 cm −1 (103 kcal mol −1 ), relative to the H 2 CO global minimum, using the new PES, with a particular focus on roaming dynamics. When compared with the results from PES04, the new PES findings show similar rotational distributions, somewhat more roaming and substantially higher H 2 vibrational excitation. This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces’.

scholarly journals Primary vs. secondary H-atom abstraction in the Cl-atom reaction with n-pentane

2017 ◽  
Vol 19 (2) ◽  
pp. 1614-1626 ◽  
Author(s):  
Shubhrangshu Pandit ◽  
Balázs Hornung ◽  
Greg T. Dunning ◽  
Thomas J. Preston ◽  
Kristian Brazener ◽  
...  
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Velocity Map Imaging ◽  
Trajectory Calculations ◽  
Cl Atoms ◽  
Cl Atom

Velocity map imaging measurements and quasi-classical trajectory calculations on a newly developed, global potential energy surface combine to reveal the detailed mechanisms of reaction of Cl atoms with n-pentane.

Rotational resonances in the H2CO roaming reaction are revealed by detailed correlations

Science ◽  
2020 ◽  
pp. eabc4088
Author(s):  
Mitchell S. Quinn ◽  
Klaas Nauta ◽  
Meredith J. T. Jordan ◽  
Joel M. Bowman ◽  
Paul L. Houston ◽  
...  
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Quantum State ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Trajectory Calculations

Since its discovery 16 years ago, “roaming” has become a ubiquitous mechanism in molecular photochemistry. Its general features are now understood, but little detail is known about how the potential energy surface (PES) determines reaction outcomes. We perform detailed experiments on H2CO photodissociation, determining fully correlated quantum state distributions of the H2 and CO products. These experiments reveal previously undetected bimodal CO rotational distributions. Insights from classical trajectory calculations demonstrate these features arise from resonances as the PES directs the reaction into cis and trans O–C–H···H critical geometries, which produce rebound and stripping mechanisms, respectively. These subtle and pervasive effects demonstrate additional complexity in this prototypical roaming reaction, which we expect to be general. They also provide detailed benchmarks for predictive theories of roaming.

Stereodynamics investigation of F + HO → HF + O(1D) on the ground singlet potential energy surface by means of the quasi-classical trajectory method

2014 ◽  
Vol 92 (3) ◽  
pp. 250-256 ◽  
Author(s):  
Dan Zhao ◽  
Xiaohu He ◽  
Wei Guo
Keyword(s):  
Angular Momentum ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Collision Energy ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Classical Trajectory ◽  
Rotational Excitation ◽  
Title Reaction ◽  
Trajectory Method

The stereodynamics calculation of F + HO → HF + O(1D) was carried out using the quasi-classical trajectory method on the 11A′ potential energy surface provided by Gomez-Carrasco et al. (Chem. Phys. Lett. 2007, 435, 188). The effect of the collision energy, isotopic substitution, and different initial ro-vibrational states on the reaction is discussed. It is found that for the initial ground state of HO (v = 0, j = 0), the degree of the forward scattering and the product polarizations remarkably change as the collision energy varies. Isotopic effect leads to the increase of alignment and decrease of orientation of product rotational angular momentum. Moreover, the P(θr) distribution and P(φr) distribution change noticeably by varying the initial vibrational number. The initial vibrational excitation plays a more important role in the enhancement of alignment and orientation distribution of j′ for the title reaction. Although the influence of the initial rotational excitation effect on the aligned and oriented distribution of product is not stronger than that of the initial vibrational excitation effect, the initial rotational excitation makes the alignment of the product rotational angular momentum decrease to some extent. The probabilities show that the reactivity of the title reaction strongly depends on the initial vibrational state.

scholarly journals Dissociative adsorption dynamics of nitrogen on a Fe(111) surface

2017 ◽  
Vol 19 (36) ◽  
pp. 24626-24635 ◽  
Author(s):  
M. A. Nosir ◽  
L. Martin-Gondre ◽  
G. A. Bocan ◽  
R. Díez Muiño
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Density Functional ◽  
Energy Surface ◽  
Dissociative Adsorption ◽  
Classical Trajectory ◽  
Functional Theory ◽  
Adsorption Dynamics ◽  
Trajectory Calculations

The dissociative adsorption dynamics of N2 on clean Fe(111) surfaces is theoretically investigated by means of quasi-classical trajectory calculations based on a multidimensional potential energy surface built from density functional theory.

Quasi-classical trajectory calculations on a fast analytic potential energy surface for the C(1D)+H2 reaction

2003 ◽  
Vol 374 (3-4) ◽  
pp. 243-251 ◽  
Author(s):  
Luis Bañares ◽  
F.J. Aoiz ◽  
Saulo A. Vázquez ◽  
Tak-San Ho ◽  
Herschel Rabitz
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Trajectory Calculations ◽  
Analytic Potential

Isotope-selective chemistry in the Be+(2S1/2) + HOD → BeOD+/BeOH+ + H/D reaction

2019 ◽  
Vol 21 (26) ◽  
pp. 14005-14011 ◽  
Author(s):  
Gary K. Chen ◽  
Changjian Xie ◽  
Tiangang Yang ◽  
Anyang Li ◽  
Arthur G. Suits ◽  
...  
Keyword(s):  
Low Temperature ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Electronic State ◽  
Energy Surface ◽  
Ion Trap ◽  
Zero Point ◽  
Classical Trajectory ◽  
Deuterated Water ◽  
Trajectory Calculations

Low temperature reactions between laser-cooled Be+(2S1/2) ions and partially deuterated water (HOD) molecules have been investigated using an ion trap and interpreted with zero-point corrected quasi-classical trajectory calculations on a highly accurate global potential energy surface for the ground electronic state.

A quasi-classical trajectory study of the reagent initial rotation quantum state effect on the reaction He + T2+ → HeT+ + T using an improved ab initio potential energy surface

2012 ◽  
Vol 90 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Ningjiu Zhao ◽  
Yufang Liu
Keyword(s):  
Angular Momentum ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Quantum Number ◽  
Relative Velocity ◽  
Energy Surface ◽  
Rotational Quantum Number ◽  
Chem Phys ◽  
Classical Trajectory ◽  
Positive Direction

In this work, we employed the quasi-classical trajectory (QCT) method to study the vector correlations and the influence of the reagent initial rotational quantum number j for the reaction He + T2+ (v = 0, j = 0–3) → HeT+ + T on a new potential energy surface (PES). The PES was improved by Aquilanti co-workers (Chem. Phys. Lett. 2009. 469: 26–30). The polarization-dependent differential cross sections (PDDCSs) and the distributions of P(θr), P([Formula: see text]r), and P(θr, [Formula: see text]r) are presented in this work. The plots of the PDDCSs provide us with abundant information about the distribution of the product angular momentum polarization. The P(θr) is used to describe the correlation between k (the relative velocity of the reagent) and j′ (the product rotational angular momentum). The distribution of dihedral angle P([Formula: see text]r) shows the k–k′–j′ (k′ refers to the relative velocity of the product) correlation. The PDDCS calculations illustrate that the product of this reaction is mainly backward scatter and it has the strongest polarization in the backward and sideways scattering directions. At the same time, the results of the P([Formula: see text]r) demonstrate that the product HeT+ tends to be oriented along the positive direction of the y axis and it tends to rotate right-handedly in planes parallel to the scattering plane. Moreover, the distribution of the P(θr) manifests that the product angular momentum is aligned along different directions relative to k. The direction of the product alignment may be perpendicular, opposite, or parallel to k. Moreover, our calculations are independent of the initial rotational quantum number.

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