Effects of dephasing and vibronic structure on the first hyperpolarizability of strong charge transfer molecules

2000 ◽  
Author(s):  
Chin H. Wang
Keyword(s):  
Charge Transfer ◽  
First Hyperpolarizability ◽  
Vibronic Structure

scholarly journals Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

2019 ◽  
Author(s):  
Pralok K. Samanta ◽  
Md Mehboob Alam ◽  
Ramprasad Misra ◽  
Swapan K. Pati
Keyword(s):  
Charge Transfer ◽  
Gas Phase ◽  
Density Functional ◽  
Intramolecular Charge Transfer ◽  
Photon Absorption ◽  
First Hyperpolarizability ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Nlo Response ◽  
Donor Acceptor

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (β<sub>total</sub>) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (β<sub>vec</sub>) to β<sub>total</sub> also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.<br>

Charge transfer and first hyperpolarizability: cage-like radicals C59X and lithium encapsulated Li@C59X (X=B, N)

2015 ◽  
Vol 21 (10) ◽  
Author(s):  
Feng-Wei Gao ◽  
Rong-Lin Zhong ◽  
Shi-Ling Sun ◽  
Hong-Liang Xu ◽  
Liang Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
First Hyperpolarizability

Vibronic Structure of PTCDA Stacks: Monomer-Dimer Equilibrium

1999 ◽  
Vol 598 ◽  
Author(s):  
Zoltán G. Soos ◽  
Margaret H. Hennessy ◽  
Vladimir Bulovic
Keyword(s):  
Charge Transfer ◽  
Strong Coupling ◽  
Molecular Vibration ◽  
Vibronic Structure ◽  
Crystalline Films ◽  
Charge Transfer Excitons

ABSTRACTSolution spectra of perylenetetracarboxylic dianhydride (PTCDA) show an equilibrium between monomers and dimers, with fluorescence exclusively from monomers and absorption from both. The dimer absorption follows closely the spectrum of PTCDA stacks in crystalline films, which indicate strong coupling to a molecular vibration and mixing of Frenkel and charge-transfer excitons. The same model accounts for solution spectra.

Electronic and vibronic structure of the nonplanar organic charge-transfer salt m-BDNT-PF6

1996 ◽  
Vol 195 (2) ◽  
pp. 611-623 ◽  
Author(s):  
J. Dong ◽  
K. Yakushi ◽  
Y. Yamashita ◽  
K. Imaeda ◽  
H. Inokuchi
Keyword(s):  
Charge Transfer ◽  
Vibronic Structure

scholarly journals Density Functional Theory Study of Substitution Effects on the Second-Order Nonlinear Optical Properties of Lindquist-Type Organo-Imido Polyoxometalates

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1636
Author(s):  
Emna Rtibi ◽  
Benoit Champagne
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Density Functional ◽  
Energy Charge ◽  
Substitution Effects ◽  
First Hyperpolarizability ◽  
Functional Theory ◽  
State Approximation ◽  
Donor And Acceptor

Density functional theory and time-dependent density functional theory have been enacted to investigate the effects of donor and acceptor on the first hyperpolarizability of Lindquist-type organo-imido polyoxometalates (POMs). These calculations employ a range-separated hybrid exchange-correlation functional (ωB97X-D), account for solvent effects using the implicit polarizable continuum model, and analyze the first hyperpolarizabilities by using the two-state approximation. They highlight the beneficial role of strong donors as well as of π-conjugated spacers (CH=CH rather than C≡C) on the first hyperpolarizabilities. Analysis based on the unit sphere representation confirms the one-dimensional push-pull π-conjugated character of the POMs substituted by donor groups and the corresponding value of the depolarization ratios close to 5. Furthermore, the use of the two-state approximation is demonstrated to be suitable for explaining the origin of the variations of the first hyperpolarizabilities as a function of the characteristics of a unique low-energy charge-transfer excited state and to attribute most of the first hyperpolarizability changes to the difference of dipole moment between the ground and that charge-transfer excited state.

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