Photochemical reactions of the low-lying excited states of formaldehyde: T1/S0 intersystem crossings, characteristics of the S1 and T1 potential energy surfaces, and a global T1 potential energy surface

2009 ◽  
Vol 130 (11) ◽  
pp. 114304 ◽  
Author(s):  
Peng Zhang ◽  
Satoshi Maeda ◽  
Keiji Morokuma ◽  
Bastiaan J. Braams
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Photochemical Reactions ◽  
Energy Surfaces

Potential Energy Surfaces

1996 ◽  
Author(s):  
Tomas Baer ◽  
William L. Hase
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Electronic State ◽  
Diatomic Molecule ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Electronic States ◽  
Dissociation Energies ◽  
State Potential ◽  
Energy Surfaces

Properties of potential energy surfaces are integral to understanding the dynamics of unimolecular reactions. As discussed in chapter 2, the concept of a potential energy surface arises from the Born-Oppenheimer approximation, which separates electronic motion from vibrational/rotational motion. Potential energy surfaces are calculated by solving Eq. (2.3) in chapter 2 at fixed values for the nuclear coordinates R. Solving this equation gives electronic energies Eie(R) at the configuration R for the different electronic states of the molecule. Combining Eie(R) with the nuclear repulsive potential energy VNN(R) gives the potential energy surface Vi(R) for electronic state i (Hirst, 1985). Each state is identified by its spin angular momentum and orbital symmetry. Since the electronic density between nuclei is different for each electronic state, each state has its own equilibrium geometry, sets of vibrational frequencies, and bond dissociation energies. To illustrate this effect, vibrational frequencies for the ground singlet state (S0) and first excited singlet state (S1) of H2CO are compared in table 3.1. For a diatomic molecule, potential energy surfaces only depend on the internuclear separation, so that a potential energy curve results instead of a surface. Possible potential energy curves for a diatomic molecule are depicted in figure 3.1. Of particular interest in this figure are the different equilibrium bond lengths and dissociation energies for the different electronic states. The lowest potential curve is referred to as the ground electronic state potential. The primary focus of this chapter is the ground electronic state potential energy surface. In the last section potential energy surfaces are considered for excited electronic states. A unimolecular reactant molecule consisting of N atoms has a multidimensional potential energy surface which depends on 3N-6 independent coordinates. For the smallest nondiatomic reactant, a triatomic molecule, the potential energy surface is four-dimensional (three independent coordinates plus the energy). Since it is difficult, if not impossible, to visualize surfaces with more than three dimensions, methods are used to reduce the dimensionality of the problem in portraying surfaces. In a graphical representation of a surface the potential energy is depicted as a function of two coordinates with constraints placed on the remaining 3N-8 coordinates.

Triangulation of the Lowest Energy Sheet for Jahn-Teller Potential Energy Surfaces

1986 ◽  
Vol 41 (3) ◽  
pp. 532-534
Author(s):  
Ariel Fernández
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Potential Energy Surfaces ◽  
Lower Energy ◽  
Energy Surface ◽  
Teller Effect ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Energy Surfaces

The topology of the lower energy sheet for the Potential Energy Surface corresponding to the dynamic Jahn-Teller effect is obtained by means of homological techniques.

Collisional excitation of CH(X2Π) by He: new ab initio potential energy surfaces and scattering calculations

2015 ◽  
Vol 17 (33) ◽  
pp. 21583-21593 ◽  
Author(s):  
Sarantos Marinakis ◽  
Indigo Lily Dean ◽  
Jacek Kłos ◽  
François Lique
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Experimental Results ◽  
Collisional Excitation ◽  
Energy Surfaces

We present a new CH(X)–He potential energy surface which is able to reproduce all the available experimental results.

scholarly journals Accurate reproducing kernel-based potential energy surfaces for the triplet ground states of N2O and dynamics for the N + NO ↔ O + N2 and N2 + O → 2N + O reactions

2020 ◽  
Vol 22 (33) ◽  
pp. 18488-18498 ◽  
Author(s):  
Debasish Koner ◽  
Juan Carlos San Vicente Veliz ◽  
Raymond J. Bemish ◽  
Markus Meuwly
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Vibrational Relaxation ◽  
Potential Energy Surfaces ◽  
Reproducing Kernel ◽  
Energy Surface ◽  
Ground States ◽  
Triplet States ◽  
Dynamical Study ◽  
Energy Surfaces

Reproducing kernel-based potential energy surface based on MRCI+Q/aug-cc-pVTZ energies for the triplet states of N2O and quasiclassical dynamical study for the reaction, dissociation and vibrational relaxation.

FISSION POTENTIAL ENERGY SURFACES IN TEN-DIMENSIONAL DEFORMATION SPACE

2009 ◽  
Vol 18 (04) ◽  
pp. 907-913 ◽  
Author(s):  
V. PASHKEVICH ◽  
Y. PYATKOV ◽  
A. UNZHAKOVA
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Correction Method ◽  
Shell Correction ◽  
Deformation Space ◽  
Complete Deformation ◽  
Energy Surfaces ◽  
Cold Fission

Various fission processes are described in terms of high-dimensional potential energy surface in the frame of the Strutinsky shell correction method for actinide region. The complete deformation space is necessary to study the potential energy minima responsible for the cluster radioactivity, cold fission and cold multi-fragmentation valleys. The nuclear shape families for the different fission configurations are obtained without any specific change of the parameters. The coordinate system based on the Cassini ovaloids makes it possible to increase the number of independent deformation parameters without divergence. The higher orders of the deformation are shown to play an important role in the description of the potential energy surface structure.

Mathematical Modeling of the Structures and Bulk Moduli of TX2 Quartz and Cristobalite Structure-Types, T = C,Si,Ge and X = O,S

1988 ◽  
Vol 121 ◽  
Author(s):  
G. V. Gibbs ◽  
M. B. Boisen ◽  
R. T. Downs ◽  
A. C. Lasaga
Keyword(s):  
Mathematical Modeling ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Bulk Modulus ◽  
Small Molecules ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Mo Calculations ◽  
Bending Force ◽  
Energy Surfaces

ABSTRACTModels of the oxide and sulfide structure-types of quartz and cristobalite have been made using potential energy surfaces derived from MO calculations on small molecules. The bond length and angle and the volume compressibility data calculated for quartz match those observed for pressures up to 40 kbars. An analysis of the force constants that define the potential energy surface indicates that the bulk modulus of the mineral is governed primarily by the bending force constant of the bridging angle. Similar calculations were completed for the GeO2 form of quartz, but the agreement with the observed data is somewhat poorer. A modeling of the CO2 form of quartz predicts that it would be significantly harder, more incompressible and show less expansibility than the SiO2 form.

scholarly journals Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Simon Schreck ◽  
Annette Pietzsch ◽  
Brian Kennedy ◽  
Conny Såthe ◽  
Piter S. Miedema ◽  
...  
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
State Potential ◽  
Energy Surfaces ◽  
Ray Scattering

Abstract Thermally driven chemistry as well as materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.

Theoretical investigation on the reaction of HS+ with CH3NH2

2014 ◽  
Vol 68 (1) ◽  
Author(s):  
Li-Li Zhang ◽  
Hui-Ling Liu ◽  
Hao Tang ◽  
Xu-Ri Huang
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
The Other ◽  
Stationary Points ◽  
Title Reaction ◽  
Singlet Potential Energy Surface ◽  
Reaction Channels ◽  
Energy Surfaces

AbstractThe singlet and triplet potential energy surfaces for the reaction of HS+ with the simplest primary amine, CH3NH2, were determined at the CCSD(T)/6-311+G(d,p) level using the B3LYP/6-311G(d,p) and QCISD/6-311G(d,p) geometries. All possible reaction channels were explored. The results show that three paths on the singlet potential energy surface and one path on the triplet potential energy surface are competitive. These four feasible paths provide products which are presented in the paper and they are consistent with previous experimental results. On the other hand, the stationary points involved in the most favourable path all lie below those of the reactant and thus the title reaction is expected to be rapid, which is also consistent with the experiment.

Collisional excitation of interstellar PO(X2Π) by He: new ab initio potential energy surfaces and scattering calculations

2018 ◽  
Vol 20 (8) ◽  
pp. 5407-5414 ◽  
Author(s):  
François Lique ◽  
Izaskun Jiménez-Serra ◽  
Serena Viti ◽  
Sarantos Marinakis
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Inelastic Scattering ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Quantum Scattering ◽  
Collisional Excitation ◽  
Energy Surfaces

The inelastic scattering of PO (X, v = 0) has been investigated by quantum scattering calculations using a new potential energy surface.

A unified cost effective method for construction of reliable potential energy surfaces for H2S and H2O clusters

2021 ◽  
Author(s):  
Monu Morwal ◽  
Binod Kumar Oram ◽  
Biman Bandyopadhyay
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Cost Effective ◽  
Geometrical Parameters ◽  
Cost Effective Method ◽  
Energy Surfaces ◽  
Good Agreement

A DFT based methodology has been used to construct the potential energy surface of H2S clusters up to pentamer. Geometrical parameters and energetics show very good agreement with existing experimental...

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