Exploration of hydrogen bond networks and potential energy surfaces of methanol clusters using a two-stage clustering algorithm

2017 ◽  
Vol 19 (1) ◽  
pp. 544-556 ◽  
Author(s):  
Po-Jen Hsu ◽  
Kun-Lin Ho ◽  
Sheng-Hsien Lin ◽  
Jer-Lai Kuo
Keyword(s):  
Hydrogen Bond ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Clustering Algorithm ◽  
Energy Surface ◽  
Hydrogen Bond Network ◽  
Two Stage ◽  
Hydrogen Bond Networks ◽  
Bond Network ◽  
Energy Surfaces

A two-stage algorithm based both on the similarity in shape and hydrogen bond network is developed to explore the potential energy surface of methanol clusters.

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.

A theoretical and experimental investigation of some unusual intermolecular hydrogen-bond IR bands — Appearances can be deceptive

2006 ◽  
Vol 84 (10) ◽  
pp. 1371-1379 ◽  
Author(s):  
Grzegorz Litwinienko ◽  
Gino A DiLabio ◽  
K U Ingold
Keyword(s):  
Hydrogen Bond ◽  
Complex Formation ◽  
Ethylene Oxide ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Intermolecular Hydrogen Bond ◽  
Phenyl Group ◽  
Fermi Resonance ◽  
Energy Surfaces ◽  
Ir Bands

The IR spectra of the O-H stretch for hydrogen bonds (HBs) arising from complex formation between the HB donor (HBD), 4-fluorophenol, and the HB acceptors, peroxides and ethers, frequently show asymmetry that appears to arise from two incompletely resolved bands from two different complexes, but the O-H HB bands with the HBD methanol are symmetric (M. Berthelot, F. Bessau, and C. Laurence. Eur. J. Org. Chem. 925 (1998)). The present studies show that this difference in O-H HB band shapes also is true for other phenols and alcohols. However with ethylene oxide, 4-fluorophenol gives an almost symmetric O-H HB band with a very broad maximum, while alcohols give symmetric O-H HB bands with well-defined maxima. It is shown by experiment that the unusual O-H HB band shapes for the phenols are not due to Fermi resonance and are unrelated to the enthalpies of HB complex formation. Theoretical exploration of the potential energy (PE) surfaces for complexes of 4-fluorophenol and methanol with tert-butyl methyl ether and ethylene oxide reveals that O-H HB band asymmetry or broadness cannot be ascribed to the presence of two different HB complexes. For this ether, the PE surfaces for rotation about the HB and for up-and-down motion of the HBD with respect to the COC plane of the ether are relatively symmetric for methanol, but are strongly asymmetric for 4-fluorophenol, hence the differences in the O-H HB band shapes. The PE surfaces for the epoxide are effectively symmetric, but the PE for rotation about the HB has a single broad minimum for methanol, whereas with 4-fluorophenol there are two minima owing to attractive interactions between the phenyl group and the CH2 groups of the epoxide. The previously unknown β2H values for ethylene oxide and tetramethylethylene oxide are 0.36 and 0.58, respectively.Key words: asymmetric IR O-H bands, asymmetric potential energy surfaces, hydrogen-bonded complexes, hydrogen bond enthalpy, O-H frequency shift.

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.

The Diatomics-in-Molecules Method as a Means for Predicting Potential-Energy-Surface Topolology.A Case Study for the Reaction of C+ with O2

1998 ◽  
Vol 63 (9) ◽  
pp. 1329-1342
Author(s):  
Rudolf Polák
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Energy Correlation ◽  
Potential Wells ◽  
Channel Effects ◽  
Atomic States ◽  
Energy Surfaces ◽  
Mechanism Of The Reaction

Energy correlation diagrams constructed by means of a Diatomics-in-molecules model, based on the minimum basis of atomic states, indicate some unexpected features of the potential energy surfaces governing the C+ + O2 reaction. Confirmation of the early down-hill character of doublet surfaces and the presence of potential wells in C2v configurations could rise new aspects of the dynamics and mechanism of the reaction, because it is believed that entrance channel effects are very important in this reaction.

1H,2D,3C NMR Investigation of the Potential Energy Surfaces and of the Proton Exchange Mechanisms Through Hydrogen Bond

1979 ◽  
pp. 489-489
Author(s):  
N. N. Shapet’ko ◽  
Yu. S. Bogachev ◽  
I. L. Radushnova ◽  
S. S. Berestova ◽  
D. N. Shigorin ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Proton Exchange ◽  
Energy Surfaces

in the electronic triplet state: current status

2006 ◽  
Vol 364 (1848) ◽  
pp. 2889-2901 ◽  
Author(s):  
Alexander Alijah ◽  
António J.C Varandas
Keyword(s):  
Potential Energy ◽  
Triplet State ◽  
Potential Energy Surfaces ◽  
Energy Surface ◽  
Theoretical Work ◽  
Current Status ◽  
Analytical Potential ◽  
Rovibrational States ◽  
Energy Surfaces ◽  
State 1

We review the theoretical work carried out on the tri-hydrogen ion in the electronic triplet state 1 3 E ′, which is split into a and 2 3 A ′ by vibronic interaction. We begin with an overview on analytical potential energy surfaces and calculations of rovibrational states by focusing on our own results, which are based on the most accurate potential energy surfaces available so far. This is followed by an examination of the selection rules and predictions of infrared transition frequencies. Finally, we discuss the Slonczewski resonance states supported by the upper sheet of the potential energy surface. Theoretical work reported here may be of interest for future experiments on the title ion.

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.

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