Trans–cis photoisomerization of azobenzene by n→π* excitation: A semiclassical dynamics study

Yuan, Shuai; Wu, Wei; Dou, Yusheng; Zhao, Jian

doi:10.1016/j.cclet.2008.07.007

Cited by 8 publications

(5 citation statements)

References 17 publications

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“…SERID has been used to study several photochemical reactions and was found to yield good descriptions of molecular response to ultrashort laser pulses. The examples include that the calculation of the photoisomerization mechanism of azobenzene − for nπ* and ππ* excitations. The method has also been used in biologically relevant studies such as nonadiabatic decay for adenine, photodissociation of cyclobutane thymine dimer and photoinduced dimerization of thymine, and deactivation via long-lived excimers of stacked adenines. , All the results were found to be consistent with experimental observations.…”

Section: Methodsmentioning

confidence: 99%

Detailed Mechanism for Photoinduced Cytosine Dimerization: A Semiclassical Dynamics Simulation

et al. 2011

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Semiclassical dynamics simulation is used to study dimerization of two stacked cytosine molecules following excitation by ultrashort laser pulses (25 fs fwhm, Gaussian, 4.1 eV photon energy). The initial excited state was found to form an ultrashort exciton state, which eventually leads to the formation of an excimer state by charge transfer. When the interbase distance, defined as an average value of C(5)-C(5)' and C(6)-C(6)', becomes less than 3 Å, charge recombination occurs due to strong intermolecular interaction, eventually leading to an avoided crossing within 20-30 fs. Geometries at the avoided crossing, with average intermolecular distance of about 2.1 Å, are in accord with CASSCF/CASPT2 calculations. Results indicate that the C(2)-N(1)-C(6)-C(5) and C(2)'-N(1)'-C(6)'-C(5)' dihedral angles' bending vibrations play a significant role in the vibronic coupling between the HOMO and LUMO, which leads to a nonadiabatic transition to the electronic ground state.

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Section: Methodsmentioning

confidence: 99%

Detailed Mechanism for Photoinduced Cytosine Dimerization: A Semiclassical Dynamics Simulation

et al. 2011

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“…The examples include that the calculation of the formation of the tetramethylene intermediate diradical is consistent with time-of-flight mass spectrometry measurements, the nonthermal fragmentation of C 60 is in good agreement with experimental observations, and the characterization of the geometry changes at some critical points is compatible with molecular mechanics valence bond calculations. We also studied the photoisomerization mechanism of azobenzene by n π* excited and isomerization quantum yield in both n π* and ππ* excited. The results are compatible with experimental observations.…”

Section: Methodsmentioning

confidence: 99%

Photoinduced Thymine Dimerization Studied by Semiclassical Dynamics Simulation

Zhang

Yuan

et al. 2009

J. Phys. Chem. C

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Response to ultrashort laser pulses of two stacked thymine molecules has been studied by semiclassical dynamics simulation with laser radiation explicitly incorporated. The laser pulses used to excite the thymine molecule have a 25 (fwhm) fs Gaussian shape with a photon energy of 4.0 eV. Simulation follows two different reaction paths produced by the laser pulses with two different fluences. In one reaction, the stacked thymine molecules form a cyclobutane pyrimidine dimer, which is the main course of photoinduced DNA damage, and the formation of two chemical bonds linking two thymines occurs nonsynchronously after the excimer decays to electronic ground state. In the other reaction, only one bond is formed between the two thymine molecules. In the second reaction, the bond breaks about 50 fs after formation, and then the two molecules move away from each other. This reaction leads to the DNA damage repair. The simulation finds that the deformation of the pyrimidine ring plays an important role in cleaving this bond.

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“…Theoretical calculations predict that AB quickly relaxes to the S 1 state after S 2 ' S 0 excitation, followed by isomerization by concerted inversion. 57,81,100,[108][109][110] Dynamic simulations 59,71,[111][112][113][114][115][116][117][118] and other ab initio calculations 119,120 predict a different relaxation pathway following S 2 ' S 0 excitation of t-AB. The S 2 state may relax directly to the S 1 state or to an alternative intermediate state, 59,119 which then relaxes to the S 1 state.…”

Section: Excited Statesmentioning

confidence: 99%

Photoisomerization in different classes of azobenzene

2012

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Azobenzene undergoes trans→cis isomerization when irradiated with light tuned to an appropriate wavelength. The reverse cis→trans isomerization can be driven by light or occurs thermally in the dark. Azobenzene's photochromatic properties make it an ideal component of numerous molecular devices and functional materials. Despite the abundance of application-driven research, azobenzene photochemistry and the isomerization mechanism remain topics of investigation. Additional substituents on the azobenzene ring system change the spectroscopic properties and isomerization mechanism. This critical review details the studies completed to date on the 3 main classes of azobenzene derivatives. Understanding the differences in photochemistry, which originate from substitution, is imperative in exploiting azobenzene in the desired applications.

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Trans–cis photoisomerization of azobenzene by n→π* excitation: A semiclassical dynamics study

Cited by 8 publications

References 17 publications

Detailed Mechanism for Photoinduced Cytosine Dimerization: A Semiclassical Dynamics Simulation

Detailed Mechanism for Photoinduced Cytosine Dimerization: A Semiclassical Dynamics Simulation

Photoinduced Thymine Dimerization Studied by Semiclassical Dynamics Simulation

Photoisomerization in different classes of azobenzene

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