Experimental Determination of Vibrational Potential Energy Surfaces and Molecular Structures in Electronic Excited States

2000 ◽  
Vol 104 (33) ◽  
pp. 7715-7733 ◽  
Author(s):  
Jaan Laane
Keyword(s):  
Potential Energy ◽  
Experimental Determination ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Molecular Structures ◽  
Electronic Excited States ◽  
Energy Surfaces

The search for fluorescence and the study of radiationless transitions of electronic excited states of NH3+

1985 ◽  
Vol 63 (7) ◽  
pp. 1386-1389 ◽  
Author(s):  
Gérald Dujardin ◽  
Sydney Leach
Keyword(s):  
Quantum Yield ◽  
Potential Energy ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Dissociation Limit ◽  
Experimental Conditions ◽  
Electronic Excited States ◽  
Intramolecular Quenching ◽  
Upper Limits ◽  
Energy Surfaces

Photoion – fluorescence photon coincidence experiments were carried out in order to detect the fluorescence of NH3+ which is expected to occur from that part of its à electronic state that lies below the lowest dissociation limit. Hel and Nel sources were used to produce the ions. No NH3+ fluorescence was detected and upper limits for its quantum yield under our experimental conditions are given. We show that the lifetime of the à state is probably very long, making it difficult to observe fluorescence. Furthermore, we argue that the molecular parameters and potential energy surfaces of the à and [Formula: see text] states are such that resonance limit nonradiative coupling to high rovibrational levels of the [Formula: see text] state could be an efficient process for apparent intramolecular quenching of NH3+à state fluorescence.

scholarly journals Torsional Potential Energy Surfaces of Dinitrobenzene Isomers

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Paul M. Smith ◽  
Mario F. Borunda
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Three Dimensional ◽  
Molecular Structures ◽  
Basis Sets ◽  
Valuable Insight ◽  
Complex Molecules ◽  
Torsional Potential ◽  
Energy Surfaces

The torsional potential energy surfaces of 1,2-dinitrobenzene, 1,3-dinitrobenzene, and 1,4-dinitrobenzene were calculated using the B3LYP functional with 6-31G(d) basis sets. Three-dimensional energy surfaces were created, allowing each of the two C-N bonds to rotate through 64 positions. Dinitrobenzene was chosen for the study because each of the three different isomers has widely varying steric hindrances and bond hybridization, which affect the energy of each conformation of the isomers as the nitro functional groups rotate. The accuracy of the method is determined by comparison with previous theoretical and experimental results. The surfaces provide valuable insight into the mechanics of conjugated molecules. The computation of potential energy surfaces has powerful application in modeling molecular structures, making the determination of the lowest energy conformations of complex molecules far more computationally accessible.

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 DFT Study on Adsorption of Acetone and Toluene on Silicene

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Pham Trong Lam ◽  
Ta Thi Luong ◽  
Vo Van On ◽  
An Dinh Van
Keyword(s):  
Charge Transfer ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Adsorption Mechanism ◽  
Simulation Method ◽  
Dft Study ◽  
Gap Opening ◽  
Energy Surfaces ◽  
And Diffusion

In this work, we investigated the adsorption mechanism of acetone and toluene on the surface of silicene by the quantum simulation method. The images of the potential energy surfaces for different positions of the adsorbate on the silicene surface were explored by Computational DFT-based Nanoscope tool for determination of the most stable configurations and diffusion possibilities. The charge transfer in order of 0.2 – 0.3 electrons and the tunneling gap opening of 18 – 23 meV due to acetone and toluene, respectively, suggest that silicene is considerably sensitive with these VOCs and can be used as the material in the fabrication of reusable VOC sensors.

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