Following the excited state relaxation dynamics of indole and 5-hydroxyindole using time-resolved photoelectron spectroscopy J. Chem. Phys. 135, 194307 (2011) Population inversion of molecular nitrogen in an Ar: N2 mixture by selective resonance-enhanced multiphoton ionization J. Appl. Phys. 110, 083112 (2011) Control of vibronic excitation using quantum-correlated photons J. Chem. Phys. 135, 164304 (2011) Resonant two-photon ionization spectroscopy of jet-cooled PdSi J. Chem. Phys. 135, 134308 (2011) Optical purification of a mixture of chiral forms by dimer formation J. Chem. Phys. 135, 124304 (2011) Additional information on J. Chem. Phys. In this study, the one-and two-photon absorption spectra of seven azoaromatic compounds ͑five pseudostilbenes-type and two aminoazobenzenes͒ were theoretically investigated using the density functional theory combined with the response functions formalism. The equilibrium molecular structure of each compound was obtained at three different levels of theory: Hartree-Fock, density functional theory ͑DFT͒, and Møller-Plesset 2. The effect of solvent on the equilibrium structure and the electronic transitions of the compounds were investigated using the polarizable continuum model. For the one-photon absorption, the allowed → ء transition energy showed to be dependent on the molecular structures and the effect of solvent, while the n → ء and → ء ͑n͒ transition energies exhibited only a slight dependence. An inversion between the bands corresponding to the → ء and n → ء states due to the effect of solvent was observed for the pseudostilbene-type compounds. To characterize the allowed two-photon absorption transitions for azoaromatic compounds, the response functions formalism combined with DFT using the hybrid B3LYP and PBE0 functionals and the long-range corrected CAM-B3LYP functional was employed. The theoretical results support the previous findings based on the three-state model. The model takes into account the ground and two electronic excited states and has already been used to describe and interpret the two-photon absorption spectrum of azoaromatic compounds. The highest energy two-photon allowed transition for the pseudostilbene-type compounds shows to be more effectively affected ͑ϳ20%͒ by the torsion of the molecular structure than the lowest allowed transition ͑ϳ10%͒. In order to elucidate the effect of the solvent on the two-photon absorption spectra, the lowest allowed two-photon transition ͑dipolar transition͒ for each compound was analyzed using a two-state approximation and the polarizable continuum model. The results obtained reveal that the effect of solvent increases drastically the two-photon cross-section of the dipolar transition of the pseudostilbene-type compounds. In general, the features of both one-and two-photon absorption spectra of the azoaromatic compounds are well reproduced by the theoretical calculations.
A theoretical analysis of the linear and nonlinear optical properties of six push-pull pi-conjugated molecules with stilbene, azobenzene and benzilideneaniline as a backbone is presented. The photophysical properties of the investigated systems were determined by using response functions combined with density functional theory (DFT). Several different exchange-correlation potentials were applied in order to determine parameters describing the one- and two-photon spectra of the studied molecules. In particular, the recently proposed Coulomb-attenuated model (CAM-B3LYP) was used to describe charge-transfer (CT) excited states. In order to compare theoretical predictions with available experimental data, calculations with inclusion of solvent effects were performed. The BLYP and the CAM-B3LYP functionals were found to yield values of two-photon absorption (TPA) probabilities closer to experimental values than the B3LYP functional or the HF wavefunction. Moreover, molecular static hyperpolarisabilities were determined using both DFT and second-order Møller-Plesset perturbation (MP2) theory. Likewise, the CAM-B3LYP functional was found to outperform other applied exchange-correlation potentials in determining first hyperpolarisability (beta). Moreover, it was confirmed on a purely theoretical basis that the presence of a -C=C- bridge between the phenyl rings leads to a much larger nonlinear optical response in comparison with a -N=N- bridge.
In this study we report on the electronic and vibrational (hyper)polarizabilities of donor-acceptorsubstituted azobenzene. It is observed that both electronic and vibrational contributions to the electric dipole first hyperpolarizability of investigated photoactive molecule substantially depend on the conformation. The contributions to the nuclear relaxation first hyperpolarizability are found to be quite important in the case of two considered isomers (cis and trans). Although the double-harmonic term is found to be the largest in terms of magnitude, it is shown that the total value of the nuclear relaxation contribution to vibrational first hyperpolarizability is a result of subtle interplay of higher-order contributions. As a part of the study, we also assess the performance of long-range-corrected density functional theory in determining vibrational contributions to electric dipole (hyper)polarizabilities. In most cases, the applied long-range-corrected exchange-correlation potentials amend the drawbacks of their conventional counterparts.
The absorption and emission spectra of three azo sulfonamide compounds in different solvents were investigated theoretically by using response functions combined with density functional theory (DFT), while the solvent effect on the structure and the electronic transitions was determined using the integral equation formalism for the polarizable continuum model (IEF-PCM). The results show that the applied different exchange-correlation functionals can reproduce the experimental values well. DFT calculations of the title compounds showed that the H-bond formed between the solute and solvent molecules is one of the major causes of the reversible solvatochromism observed in measured spectra. This is due to a better stabilization of the neutral form than the zwitterionic form in the polar protic solvents, which is characteristic of the hypsochromic shift. On the other hand, the molecules considered exhibit a monotonic behavior regarding the polarity of the low-lying excited state (Δμg–CT) as a function of the solvent polarity. This dependence occurs in the case of the positive solvatochromism and confirms the thesis regarding the H-bond solute–solvent interactions. Theoretically determined values of the two-photon cross section revealed that the (σOF(2)) shows similar trends with changes in λabs, in contrast to 〈δOF〉 values. In conclusion, the results demonstrate that the investigated molecules can be used successfully as fluorochromes in bioimaging.Electronic supplementary materialThe online version of this article (doi:10.1007/s00894-015-2651-z) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.