English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Nonadiabatic dynamics simulations of photoexcited urocanic acid

Tuna, D., Spörkel, L., Barbatti, M., & Thiel, W. (2018). Nonadiabatic dynamics simulations of photoexcited urocanic acid. Chemical Physics, 515, 521-534. doi:10.1016/j.chemphys.2018.09.036.

Item is

Basic

show hide
Genre: Journal Article

Files

show Files
hide Files
:
1-s2.0-S0301010418306542-mmc1.pdf (Supplementary material), 5MB
Name:
1-s2.0-S0301010418306542-mmc1.pdf
Description:
Supporting Information
OA-Status:
Visibility:
Public
MIME-Type / Checksum:
application/pdf / [MD5]
Technical Metadata:
Copyright Date:
-
Copyright Info:
-
License:
-

Locators

show

Creators

show
hide
 Creators:
Tuna, Deniz1, Author           
Spörkel, Lasse1, Author           
Barbatti, Mario2, Author
Thiel, Walter1, Author           
Affiliations:
1Research Department Thiel, Max-Planck-Institut für Kohlenforschung, Max Planck Society, ou_1445590              
2Aix Marseille Univ, CNRS, ICR, Marseille, France, ou_persistent22              

Content

show
hide
Free keywords: UV photostability; UV filter; photoisomerization; excited state dynamics excited state deactivation; nonadiabatic dynamics; trajectory surface hopping; conical intersection; semiempirical methods; quantum chemistry; excited state intramolecular proton transfer; ESIPT; photoisomerization quantum yield
 Abstract: Urocanic acid (UA) is a UV filter found in human skin, which has been linked to photoimmunosuppression and the formation of skin cancer. Its UV-light-induced photoisomerization and radiationless deactivation mechanisms have been addressed previously by static calculations. In this paper, we present nonadiabatic trajectory-surface-hopping dynamics simulations of photoexcited UA using the semiempirical OM2/MRCI methodology and an adaptive-timestep algorithm. We have simulated almost 6000 trajectories, each for a simulation time of 1.6 ps, covering the entire conformational space of the E and Z isomers of both possible tautomers of the isolated neutral form of UA (overall 32 conformers). Initial conditions for the excited-state dynamics were obtained from 1 ns ground-state dynamics simulations. We find that UA has an ultrashort excited-state lifetime, which is due to ultrafast radiationless excited-state deactivation driven by E↔Z photoisomerization and excited-state intramolecular proton-transfer (ESIPT) processes. The computed S1 excited-state lifetimes for the E and Z isomers of the N1H and N3H tautomers range from 271 to 506 fs. The photoisomerization quantum yield is calculated to be 43% (32%) for the combined E (Z) isomers of both tautomers. The shorter lifetime and the lower photoisomerization quantum yield of the Z isomers can be rationalized by the larger number of available excited-state deactivation processes: the Z isomers can undergo ESIPT and photoisomerization, whereas the E isomers can only deactivate via the latter process. The intramolecular hydrogen bond that is present in many Z conformers can prevent successful photoisomerization to an E isomer. We find no evidence for an excitation-energy-dependent quantum yield for photoisomerization (EEDQY-PI) in isolated (E)-UA, which has previously been detected spectroscopically in aqueous solution. However, we do find an EEDQY-PI as well as a complementary excitation-energy-dependent quantum yield for ESIPT (EEDQY-ESIPT) for the N1H-Z isomers, which demonstrates the competition of the photoisomerization and ESIPT processes. The present comprehensive study lays the groundwork for future photodynamics simulations of UA in the aqueous phase.

Details

show
hide
Language(s): eng - English
 Dates: 2018-06-152018-09-242018-09-252018-11-14
 Publication Status: Published in print
 Pages: 14
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1016/j.chemphys.2018.09.036
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Chemical Physics
  Other : Chem. Phys.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Amsterdam : Elsevier B.V.
Pages: - Volume / Issue: 515 Sequence Number: - Start / End Page: 521 - 534 Identifier: ISSN: 0301-0104
CoNE: https://pure.mpg.de/cone/journals/resource/954925509371