scholarly journals Potential Energy Surfaces for Reactions of X Metal Atoms (X = Cu, Zn, Cd, Ga, Al, Au, or Hg) with YH4 Molecules (Y = C, Si, or Ge) and Transition Probabilities at Avoided Crossings in Some Cases

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Octavio Novaro ◽  
María del Alba Pacheco-Blas ◽  
Juan Horacio Pacheco-Sánchez
Keyword(s):  
Excited State ◽  
Excited States ◽  
Metal Atom ◽  
Potential Energy Surfaces ◽  
Transition Probabilities ◽  
Metal Atoms ◽  
Avoided Crossings ◽  
Reaction Barriers ◽  
Energy Surfaces

We review ab initio studies based on quantum mechanics on the most important mechanisms of reaction leading to the C–H, Si–H, and Ge–H bond breaking of methane, silane, and germane, respectively, by a metal atom in the lowest states in symmetry: X(2nd excited state, 1st excited state and ground state) + YH4 H3XYH H + XYH3 and XH + YH3. with X = Au, Zn, Cd, Hg, Al, and G, and Y = C, Si, and Ge. Important issues considered here are (a) the role that the occupation of the d-, s-, or p-shells of the metal atom plays in the interactions with a methane or silane or germane molecule, (b) the role of either singlet or doublet excited states of metals on the reaction barriers, and (c) the role of transition probabilities for different families of reacting metals with these gases, using the H–X–Y angle as a reaction coordinate. The breaking of the Y–H bond of YH4 is useful in the production of amorphous hydrogenated films, necessary in several fields of industry.

Excited State Tracking During the Relaxation of Coordination Compounds

2018 ◽  
Author(s):  
Juan Sanz García ◽  
Martial Boggio-Pasqua ◽  
Ilaria Ciofini ◽  
Marco Campetella
Keyword(s):  
Excited State ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Complex Nature ◽  
Electronic Excited States ◽  
Ruthenium Nitrosyl ◽  
State Tracking ◽  
Energy Surfaces ◽  
Electronic Wavefunction

<div>The ability to locate minima on electronic excited states (ESs) potential energy surfaces (PESs) both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small- to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic excited states close in energy, but also due to the complex nature of the excited states involved. In this article, we present a simple yet powerful method to follow an excited state of interest during a structural optimization in the case of TMC, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wavefunction overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium-nitrosyl complex which is very problematic with standard approaches.</div>

scholarly journals Beyond the Coulson–Fischer point: characterizing single excitation CI and TDDFT for excited states in single bond dissociations

2019 ◽  
Vol 21 (39) ◽  
pp. 21761-21775 ◽  
Author(s):  
Diptarka Hait ◽  
Adam Rettig ◽  
Martin Head-Gordon
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Single Bond ◽  
State Potential ◽  
Energy Surfaces ◽  
Single Bonds

HF/DFT orbitals spin-polarize when single bonds are stretched past the Coulson–Fischer point. We report unphysical features in the excited state potential energy surfaces predicted by CIS/TDDFT in this regime, and characterize their origin.

The 4s ← 1b1 and 3d ← 1b1 Rydberg states of H2O and D2O: Spectroscopy and predissociation dynamics

1984 ◽  
Vol 62 (12) ◽  
pp. 1806-1833 ◽  
Author(s):  
Michael N. R. Ashfold ◽  
J. Mark Bayley ◽  
Richard N. Dixon
Keyword(s):  
Potential Energy Surfaces ◽  
Vacuum Ultraviolet ◽  
Transition Probabilities ◽  
Line Strength ◽  
Rydberg States ◽  
Photon Ionization ◽  
The One ◽  
Energy Surfaces ◽  
Equilibrium Geometries

Two new electronic states of H2O and D2O have been identified in the energy range 84 000–88 000 cm−1 as three-photon resonances in four-photon ionization spectroscopy. Simulations of the rotational intensity distributions using asymmetric top three-photon line strength theory, and rotational analyses, characterize the states as B1 and A2. These Rydberg states are assigned to the excitations 4sa1 ← 1b1[Formula: see text] and 3d2 ← 1b1[Formula: see text] on the basis of equilibrium geometries, quantum defects, and the polarization dependence of their three-photon transition probabilities. The identification of the one-photon forbidden 1A2–1A1 transition, together with published vacuum ultraviolet (VUV) absorption spectra, permits a consistent assignment for all five members of the 3d ← 1b1 complex.The [Formula: see text] and [Formula: see text] states arc predissociatcd via both homogeneous and heterogeneous mechanisms. The homogeneous channel from the [Formula: see text] state shows a dramatic isotope effect, being about two orders of magnitude faster in H2O than from equivalent levels of D2O. The heterogeneous predissociation exhibits irregular vibronic and isotopic dependencies, which can be rationalized in terms of the intercessional role of accidental near resonances with levels of the heavily predissociated [Formula: see text] state. The (000) levels of the [Formula: see text] states of H2O and D2O show contrasting heterogeneous predissociation behaviour, which can be interpreted with a knowledge of the relevant potential energy surfaces and the electronic–rotational Coriolis interactions that couple the states.

Comparing the performance of TD-DFT and SAC-CI methods in the description of excited states potential energy surfaces: An excited state proton transfer reaction as case study

2017 ◽  
Vol 38 (14) ◽  
pp. 1084-1092 ◽  
Author(s):  
Marika Savarese ◽  
Umberto Raucci ◽  
Ryoichi Fukuda ◽  
Carlo Adamo ◽  
Masahiro Ehara ◽  
...  
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Td Dft ◽  
Excited State Proton Transfer ◽  
Energy Surfaces

Avoided crossings in excited states potential energy surfaces

1978 ◽  
Vol 100 (7) ◽  
pp. 2009-2011 ◽  
Author(s):  
A. Devaquet ◽  
A. Sevin ◽  
B. Bigot
Keyword(s):  
Potential Energy ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Avoided Crossings ◽  
Energy Surfaces

Analytical Gradients for Core-Excited States in the Algebraic Diagrammatic Construction (ADC) Framework

2021 ◽  
Author(s):  
Iulia Emilia Brumboiu ◽  
Dirk R. Rehn ◽  
Andreas Dreuw ◽  
Young Min Rhee ◽  
Patrick Norman
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Formic Acid ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
The Core ◽  
Energy Surfaces ◽  
Analytical Expressions ◽  
Analytical Gradients ◽  
Optimized Geometries

Here we present a derivation of the analytical expressions required to determine nuclear gradients for core-excited states at the core-valence separated algebraic diagrammatic construction (CVS-ADC) theory level. Analytical gradients up to and including the extended CVS-ADC(2)-x order have been derived and implemented into a Python module, adc_gradient. The gradients were used to determine core-excited state optimized geometries and relaxed potential energy surfaces for the water, formic acid, and benzne molecules. <br>

Analytical Gradients for Core-Excited States in the Algebraic Diagrammatic Construction (ADC) Framework

2021 ◽  
Author(s):  
Iulia Emilia Brumboiu ◽  
Dirk R. Rehn ◽  
Andreas Dreuw ◽  
Young Min Rhee ◽  
Patrick Norman
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Formic Acid ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
The Core ◽  
Energy Surfaces ◽  
Analytical Expressions ◽  
Analytical Gradients ◽  
Optimized Geometries

Here we present a derivation of the analytical expressions required to determine nuclear gradients for core-excited states at the core-valence separated algebraic diagrammatic construction (CVS-ADC) theory level. Analytical gradients up to and including the extended CVS-ADC(2)-x order have been derived and implemented into a Python module, adc_gradient. The gradients were used to determine core-excited state optimized geometries and relaxed potential energy surfaces for the water, formic acid, and benzne molecules. <br>

Excited State Tracking During the Relaxation of Coordination Compounds

2018 ◽  
Author(s):  
Juan Sanz García ◽  
Martial Boggio-Pasqua ◽  
Ilaria Ciofini ◽  
Marco Campetella
Keyword(s):  
Excited State ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Complex Nature ◽  
Electronic Excited States ◽  
Ruthenium Nitrosyl ◽  
State Tracking ◽  
Energy Surfaces ◽  
Electronic Wavefunction

<div>The ability to locate minima on electronic excited states (ESs) potential energy surfaces (PESs) both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small- to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic excited states close in energy, but also due to the complex nature of the excited states involved. In this article, we present a simple yet powerful method to follow an excited state of interest during a structural optimization in the case of TMC, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wavefunction overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium-nitrosyl complex which is very problematic with standard approaches.</div>

ChemInform Abstract: AVOIDED CROSSINGS IN EXCITED STATES POTENTIAL ENERGY SURFACES

1978 ◽  
Vol 9 (29) ◽  
Author(s):  
A. DEVAQUET ◽  
A. SEVIN ◽  
B. BIGOT
Keyword(s):  
Potential Energy ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Avoided Crossings ◽  
Energy Surfaces
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