Density Functional Static Dipole Polarizability and First-Hyperpolarizability Calculations of Nan (n = 2, 4, 6, 8) Clusters Using an Approximate CPKS Method and its Comparison with MP2 Calculations

AbstractWe report Ab Initio studies of the electric dipole polarizability of the linear polyacene series benzene through nonacene. A number of Ab Initio studies were done at different levels of theory for benzene, with all remaining Ab Initio calculations being at the B3LYP/6-311G(2d, 1p)//B3LYP/6-311+G(2d, 1p) level of theory. We find that the NN tensor component shows a constant increment of 20 atomic units per ring. AM1 and QSAR-quality empirical calculations show poor absolute agreement with the Ab Initio results but given excellent statistical correlation coefficients with the Ab Initio values. This implies that the results of such cheaper calculations can be suitably scaled for predictive purposes.

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Molecular structure, vibrational spectra, NBO analysis, first hyperpolarizability, and HOMO, LUMO studies of mesityl chloride by density functional methods

Journal of Molecular Structure ◽

10.1016/j.molstruc.2011.10.035 ◽

2012 ◽

Vol 1007 ◽

pp. 136-145 ◽

Cited By ~ 21

Author(s):

V. Balachandran ◽

K. Parimala

Keyword(s):

Molecular Structure ◽

Vibrational Spectra ◽

Density Functional ◽

Nbo Analysis ◽

First Hyperpolarizability ◽

Density Functional Methods ◽

Functional Methods ◽

Homo Lumo

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

10.26434/chemrxiv.7869062 ◽

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 (βtotal) 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 (βvec) to βtotal 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.

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Evaluation of Molecular Polarizability and of Intensity Carrying Modes Contributions in Circular Dichroism Spectroscopies

Applied Sciences ◽

10.3390/app9214691 ◽

2019 ◽

Vol 9 (21) ◽

pp. 4691 ◽

Cited By ~ 1

Author(s):

Chiara Zanchi ◽

Giovanna Longhi ◽

Sergio Abbate ◽

Giovanni Pellegrini ◽

Paolo Biagioni ◽

...

Keyword(s):

Circular Dichroism ◽

Density Functional ◽

Vibrational Circular Dichroism ◽

Molecular Polarizability ◽

Metal Nanostructures ◽

Dipole Polarizability ◽

Dft Methods ◽

Visible Absorption ◽

Long Run ◽

Circular Dichroïsm

We re-examine the theory of electronic and vibrational circular dichroism spectroscopy in terms of the formalism of frequency-dependent molecular polarizabilities. We show the link between Fermi’s gold rule in circular dichroism and the trace of the complex electric dipole–magnetic dipole polarizability. We introduce the C++ code polar to compute the molecular polarizability complex tensors from quantum chemistry outputs, thus simulating straightforwardly UV-visible absorption (UV-Vis)/electronic circular dichroism (ECD) spectra, and infrared (IR)/vibrational circular dichroism (VCD) spectra. We validate the theory and the code by referring to literature data of a large group of chiral molecules, showing the remarkable accuracy of density functional theory (DFT) methods. We anticipate the application of this methodology to the interpretation of vibrational spectra in various measurement conditions, even in presence of metal surfaces with plasmonic properties. Our theoretical developments aim, in the long run, at embedding the quantum-mechanical details of the chiroptical spectroscopic response of a molecule into the simulation of the electromagnetic field distribution at the surface of plasmonic devices. Such simulations are also instrumental to the interpretation of the experimental spectra measured from devices designed to enhance chiroptical interactions by the surface plasmon resonance of metal nanostructures.

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