scholarly journals Photochemistry of Thymine in Protic Polar Nanomeric Droplets Using Electrostatic Embeding TD-DFT/MM

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6021
Author(s):  
Miquel Huix-Rotllant
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Radiative Decay ◽  
Td Dft ◽  
Dna Photodamage ◽  
Solvent Molecules ◽  
Energy Surfaces ◽  
Electrostatic Embedding

Thymine photochemistry is important for understanding DNA photodamage. In the gas phase, thymine undergoes a fast non-radiative decay from S2 to S1. In the S1 state, it gets trapped for several picoseconds until returning to the ground-state S0. Here, we explore the electrostatic effects of nanomeric droplets of methanol and water on the excited states of thymine. For this purpose, we develop and implement an electrostatic embedding TD-DFT/MM method based on a QM/MM coupling defined through electrostatic potential fitting charges. We show that both in methanol and water, the mechanism is similar to the gas phase. The solvent molecules participate in defining the branching plane of S0/S1 intersection and have a negligible effect on the S1/S2 intersection. Despite the wrong topology of the ground/excited state intersections, electrostatic embedding TD-DFT/MM allows for a fast exploration of the potential energy surfaces and a qualitative picture of the photophysics of thymine in solvent droplets.

Modeling of clusters I. Ab initio and analytical potential energy surfaces for the ground state and two lowest excited states of

2007 ◽  
Vol 342 (1-3) ◽  
pp. 64-70 ◽  
Author(s):  
Ivana Paidarová ◽  
Rudolf Polák ◽  
Barbora Paulíková ◽  
František Karlický ◽  
Karel Oleksy ◽  
...  
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Excited States ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Analytical Potential ◽  
Energy Surfaces

scholarly journals Potential energy surfaces of ozone in its ground state and in the lowest-lying eight excited states

1993 ◽  
Vol 178 (1-3) ◽  
pp. 155-188 ◽  
Author(s):  
Antonio Banichevich ◽  
Sigrid D. Peyerimhoff ◽  
Friedrich Grein
Keyword(s):  
Potential Energy ◽  
Excited States ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Energy Surfaces

scholarly journals Role of conical intersection seam topography in the chemiexcitation of 1,2-dioxetanes

2021 ◽  
Author(s):  
Ignacio Fernández Galván ◽  
Anders Brakestad ◽  
Morgane Vacher
Keyword(s):  
Excited States ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Thermal Reaction ◽  
Conical Intersection ◽  
Conical Intersections ◽  
Nonadiabatic Transition ◽  
Isolated Points ◽  
Energy Surfaces

Chemiexcitation, the generation of electronic excited states by a thermal reaction initiated on the ground state, is an essential step in chemiluminescence, and it is mediated by the presence of a conical intersection that allows a nonadiabatic transition from ground state to excited state. Conical intersections classified as sloped favor chemiexcitation over ground state relaxation. The chemiexcitation yield of 1,2-dioxetanes is known to increase upon methylation. In this work we explore to which extent this trend can be attributed to changes in the conical intersection topography or accessibility. Since conical intersections are not isolated points, but continuous seams, we locate regions of the conical intersection seams that are close to the configuration space traversed by the molecules as they react on the ground state. We find that conical intersections are energetically and geometrically accessible from the reaction trajectory, and that topographies favorable to chemiexcitation are found in all three molecules studied. Nevertheless, the results suggest that dynamic effects are more important for explaining the different yields than the static features of the potential energy surfaces.

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 Global potential energy surfaces for the H3+ system. Analytical representation of the adiabatic ground-state 1 1A′ potential

2000 ◽  
Vol 112 (3) ◽  
pp. 1240-1254 ◽  
Author(s):  
Alfredo Aguado ◽  
Octavio Roncero ◽  
César Tablero ◽  
Cristina Sanz ◽  
Miguel Paniagua
Keyword(s):  
Potential Energy ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Analytical Representation ◽  
Energy Surfaces ◽  
State 1
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