Photodissociation pathways and conical intersections in the low‐lying electronic states of SiH+2

1994 ◽  
Vol 101 (12) ◽  
pp. 10576-10601 ◽  
Author(s):  
Steve P. Mort ◽  
Neville A. Jennings ◽  
Gabriel G. Balint‐Kurti ◽  
David M. Hirst
Keyword(s):  
Electronic States ◽  
Conical Intersections

The role of pyrimidine nucleobase excimers in DNA photophysics and photoreactivity

2009 ◽  
Vol 81 (9) ◽  
pp. 1695-1705 ◽  
Author(s):  
Israel González-Ramírez ◽  
Teresa Climent ◽  
Juan José Serrano-Pérez ◽  
Remedios González-Luque ◽  
Manuela Merchán ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Quantum Chemical ◽  
Electronic States ◽  
Conical Intersections ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Dna Nucleobases ◽  
Surface Crossings

Quantum chemical studies using the accurate CASPT2//CASSCF procedure show that π-stacked interactions in biochromophores such as pyrimidine (Pyr) DNA/RNA nucleobases pairs yield excimer-like situations which behave as precursors of processes like charge transfer (CT) or photoreactivity and are the source of the emissive properties in DNA. Examples are the CT between adjacent DNA nucleobases in a strand of oligonucleotides and the photodimerization taking place in cytosine (C) pairs leading to cyclobutanecytosine (CBC) mutants. These processes take place through nonadiabatic photochemical mechanisms whose evolution is determined by the presence and accessibility of conical intersections (CIs) and other surface crossings between different electronic states.

scholarly journals On the nonadiabatic collisional quenching of OH(A) by H2: a four coupled quasi-diabatic state description

2020 ◽  
Vol 22 (24) ◽  
pp. 13516-13527 ◽  
Author(s):  
Christopher L. Malbon ◽  
Bin Zhao ◽  
Hua Guo ◽  
David R. Yarkony
Keyword(s):  
Electronic States ◽  
Collisional Quenching ◽  
Conical Intersections

12A, 22A, and 32A electronic states of OH(A) + H2 where conical intersections facilitate the quenching of OH(A) by H2.

Conical intersections between and electronic states of

2013 ◽  
Vol 416 ◽  
pp. 11-20 ◽  
Author(s):  
Subhankar Sardar ◽  
Saikat Mukherjee ◽  
Amit Kumar Paul ◽  
Satrajit Adhikari
Keyword(s):  
Electronic States ◽  
Conical Intersections

scholarly journals Transition state dynamics of OHF on several electronic states: Photodetachment spectrum of OHF− and conical intersections

2004 ◽  
Vol 121 (20) ◽  
pp. 9865-9875 ◽  
Author(s):  
Lola González-Sánchez ◽  
Susana Gómez-Carrasco ◽  
Alfredo Aguado ◽  
Miguel Paniagua ◽  
M. Luz Hernández ◽  
...  
Keyword(s):  
Transition State ◽  
Electronic States ◽  
Conical Intersections ◽  
Photodetachment Spectrum

scholarly journals Visualizing conical intersection passages via vibronic coherence maps generated by stimulated ultrafast X-ray Raman signals

2020 ◽  
Vol 117 (39) ◽  
pp. 24069-24075
Author(s):  
Daniel Keefer ◽  
Thomas Schnappinger ◽  
Regina de Vivie-Riedle ◽  
Shaul Mukamel
Keyword(s):  
Laser Pulse ◽  
Free Electron Laser ◽  
Electronic States ◽  
Optical Excitation ◽  
Time Dependent ◽  
Conical Intersection ◽  
Energy Splitting ◽  
Conical Intersections ◽  
Strongly Coupled ◽  
X Ray

The rates and outcomes of virtually all photophysical and photochemical processes are determined by conical intersections. These are regions of degeneracy between electronic states on the nuclear landscape of molecules where electrons and nuclei evolve on comparable timescales and thus become strongly coupled, enabling radiationless relaxation channels upon optical excitation. Due to their ultrafast nature and vast complexity, monitoring conical intersections experimentally is an open challenge. We present a simulation study on the ultrafast photorelaxation of uracil, based on a quantum description of the nuclei. We demonstrate an additional window into conical intersections obtained by recording the transient wavepacket coherence during this passage with an X-ray free-electron laser pulse. Two major findings are reported. First, we find that the vibronic coherence at the conical intersection lives for several hundred femtoseconds and can be measured during this entire time. Second, the time-dependent energy-splitting landscape of the participating vibrational and electronic states is directly extracted from Wigner spectrograms of the signal. These offer a physical picture of the quantum conical intersection pathways through visualizing their transient vibronic coherence distributions. The path of a nuclear wavepacket in the vicinity of the conical intersection is directly mapped by the proposed experiment.

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