A multireference perturbation study of the NN stretching frequency of <i>trans</i>-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism

Harabuchi, Yu; Ishii, Moe; Nakayama, Akira; Noro, Takeshi; Taketsugu, Tetsuya

doi:10.1063/1.4790611

Cited by 27 publications

(41 citation statements)

References 70 publications

(98 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Fourier transformation of the time-evolution of the N = N length shows two major peaks at 1414 and 1145 cm −1 , which are consistent with the Raman spectra of photoexcited azobenzene at 1428 and 1130 cm −1 34 within the possible error caused by LDA. These peaks are also consistent with recent theoretical work with higher accuracies in many-body treatments 32 41 indicating the preservation of the double bond character of the N = N axis.…”

Section: Results For Azobenzenesupporting

confidence: 90%

See 1 more Smart Citation

Conservation of the pure adiabatic state in Ehrenfest dynamics of the photoisomerization of molecules

Miyamoto

Tateyama

Oyama

et al. 2015

Sci Rep

View full text Add to dashboard Cite

We examined real-time-propagation time-dependent density functional theory (rtp-TDDFT) coupled with molecular dynamics (MD), which uses single-particle representation of time-evolving wavefunctions allowing exchange of orbital characteristics between occupied and empty states making the effective Kohn-Sham Hamiltonian dependent on the potential energy surfaces (PESs). This scheme is expected to lead to mean-field average of adiabatic potential energy surfaces (PESs), and is one of Ehrenfest (mean-field) approaches. However, we demonstrate that the mean-field average can be absent in simulating photoisomerization of azobenzene and ethylene molecules. A transition from the S2 to the S1 excited state without the mean- field average was observed after examining several rtp-TDDFT-MD trajectories of a photoexcited azobenzene molecule. The subsequent trans-cis isomerization was observed in our simulation, which is consistent with experimental observation and supported by previous calculations. The absence of the mean-field average of PESs was also observed for the transition between the S1 and S0 states, indicating that the MD simulation was on a single PES. Conversely, we found no transition to the ground state (S0 state) when we performed a MD simulation of an S1 excited ethylene molecule owing to the constraint on the occupation number of each molecular orbital. Thus, we conclude that, at least for azobenzene and ethylene molecules, the rtp-TDDFT-MD is an on-the-fly simulation that can automatically see the transition among the PESs of excited states without the mean-field average unless the simulation reaches the PES of the S0 state.

show abstract

Section: Results For Azobenzenesupporting

confidence: 90%

“…2 . These orbital characters obtained by LDA are consistent with theoretical natural orbital plots that were obtained by the CASSCF method 32 .…”

Section: Results For Azobenzenesupporting

confidence: 87%

Conservation of the pure adiabatic state in Ehrenfest dynamics of the photoisomerization of molecules

Miyamoto

Tateyama

Oyama

et al. 2015

Sci Rep

View full text Add to dashboard Cite

show abstract

“…[20][21][22] The mechanism of the photoisomerization of azobenzene and its derivatives has been addressed in a great number of theoretical and experimental studies and several isomerization pathways have been proposed (rotation, inversion, concerted inversion, inversion-assisted rotation, and pedal motion). [23][24][25][26][27][28][29][30][31][32] However, at present, the mechanism of this process is not consensual and continues to be a challenge.…”

Section: Introductionmentioning

confidence: 99%

Photoisomerization of azobenzenes isolated in cryogenic matrices

Duarte

Khriachtchev

Fausto

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

2,2'-Dihydroxyazobenzene (DAB), 2,2'-azotoluene (AT) and azobenzene (AB) were isolated in argon and xenon matrices and their molecular structures and photochemical transformations were characterized by infrared spectroscopy and theoretical calculations. All these compounds can adopt the E and Z isomeric forms around the central CNNC moiety, which can be enriched by several conformational and tautomeric modifications for DAB and AT. A number of DAB and AT isomeric forms were identified for the first time. For DAB, the E azo-enol isomer with two intramolecular six-membered quasi-rings formed via OHN hydrogen bonds was found after deposition. Irradiation with UV light generated a different E azo-enol form with two intramolecular H-bonded five-membered quasi-rings. Phototransformation was shown to be reversible and the forms could be interconverted by irradiation at different wavelengths. The isomerization between these two forms constitutes a direct experimental observation of an E → E isomerization in azobenzene-type molecules. Further irradiation generated a form(s) bearing both OH and NH groups. For AT, two E isomers with the CH3 groups forming five-membered and five/six-membered quasi-rings with the azo group were observed in the as-deposited matrices. Irradiation of AT with UV light generated a Z form that can be converted back to the E form at different irradiation wavelengths. E-AB was deposited in a xenon matrix and both E → Z and Z → E phototransformations were observed (contrary to what was previously reported in an argon matrix where only the Z → E conversion occurred). AB photoisomerization becomes more pronounced at elevated temperatures, thus indicating that the matrix effects responsible for hindering the AB photoisomerization are essentially due to steric restrictions. The different photoisomerization channels observed for these compounds are discussed in terms of a small-amplitude pedal motion.

show abstract

“…To accommodate the observed violation of Kasha’s rule, it was therefore originally proposed that isomerization proceeds along two different pathways in the nπ* and ππ* states 5 8 9 . Over the years, extensive experimental 10 11 12 13 14 15 16 17 18 19 and theoretical 20 21 22 23 24 25 26 27 28 29 efforts have been made to elucidate the contribution of these pathways to the photoisomerization dynamics. As yet, however, there is still no consensus on the pathway, and also the interpretation of many other aspects of the excited-state dynamics are still a matter of extensive debate.…”

mentioning

confidence: 99%

Fast photodynamics of azobenzene probed by scanning excited-state potential energy surfaces using slow spectroscopy

et al. 2015

View full text Add to dashboard Cite

Azobenzene, a versatile and polymorphic molecule, has been extensively and successfully used for photoswitching applications. The debate over its photoisomerization mechanism leveraged on the computational scrutiny with ever-increasing levels of theory. However, the most resolved absorption spectrum for the transition to S1(nπ*) has not followed the computational advances and is more than half a century old. Here, using jet-cooled molecular beam and multiphoton ionization techniques we report the first high-resolution spectra of S1(nπ*) and S2(ππ*). The photophysical characterization reveals directly the structural changes upon excitation and the timescales of dynamical processes. For S1(nπ*), we find that changes in the hybridization of the nitrogen atoms are the driving force that triggers isomerization. In combination with quantum chemical calculations we conclude that photoisomerization occurs along an inversion-assisted torsional pathway with a barrier of ~2 kcal mol−1. This methodology can be extended to photoresponsive molecular systems so far deemed non-accessible to high-resolution spectroscopy.

show abstract

A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism

Cited by 27 publications

References 70 publications

Conservation of the pure adiabatic state in Ehrenfest dynamics of the photoisomerization of molecules

Conservation of the pure adiabatic state in Ehrenfest dynamics of the photoisomerization of molecules

Photoisomerization of azobenzenes isolated in cryogenic matrices

Fast photodynamics of azobenzene probed by scanning excited-state potential energy surfaces using slow spectroscopy

Contact Info

Product

Resources

About