We present a general approach for the analytic calculation of pure vibrational contributions to the molecular (hyper)polarizabilities at the density functional level of theory. The analytic approach allows us to study large molecules, and we apply the new code to the study of the first dipole hyperpolarizabilities of retinal and related molecules. We investigate the importance of electron corre...

In this work we have investigated the first hyperpolarizability of pNA in 1,4-dioxane solution using a quantum mechanics/molecular mechanics (QM/MM) model. The particular model adopted is the recently developed discrete solvent reaction field (DRF) model. The DRF model is a polarizable QM/MM model in which the QM part is treated using time-dependent density-functional theory and local-field eff...

In this thesis, new methodology of computing properties aimed for multiple applications is developed. We use quantum mechanics to compute properties of molecules, and having these properties as a basis, we set up equations based on a classical reasoning. These approximations are shown to be quite good in many cases, and makes it possible to calculate linear and non-linear properties of large sy...

Monolayers of the lipopeptide mycosubtilin are studied at the air/water interface. Their structure is investigated using molecular dynamics simulations. All-atom models suggest that the lipopeptide is flexible and aggregates at the interface. To achieve simulation times of several microseconds, a coarse-grained (CG) model based on the MARTINI force field was also used. These CG simulations desc...

The frequency-dependent vibrational second hyperpolarizability of CH42nFn molecules with n 50 – 4 has been computed for the most common nonlinear optical ~NLO! processes by adopting the perturbation approach due to Bishop and Kirtman @J. Chem. Phys. 95, 2646 ~1991!#. These calculations have been performed by using the Sadlej atomic basis set with the Hartree-Fock technique as well as with the M...

Motivated by a discrepancy of five orders of magnitude between three different hyperpolarizability measurements on the CGO fullerene, we calculated the optical response of this cluster using a tight-binding Hamiltonian and compared the results to those for a benzene molecule. Our Hamiltonian reproduces the linear polarizability and hyperpolarizability of benzene reasonably well. For C60, our ca...

Two-photon absorption (TPA) cross sections of four representative series of octupolar molecules are theoretically investigated. The general structure--TPA-property relationship is described by using the effective four-state valence-bond three-charge-transfer model. As the charge-transfer character of the ground electronic state increases due to the strong donors or acceptors, (i) the transition...

The unexpectedly high quadratic hyperpolarizability values of simple Ru and Pt alkynyl complexes have been measured by the EFISH technique, and this prompted us to investigate their potential as molecular building blocks for composite films with second harmonic generation properties.

A series of substituted 2-(2-hydroxyphenylimino) phenolic (salen) derivatives (1-4) have been synthesized and their structures of obtained compound were characterized by analytical, FT-IR, UV-Vis and C{H}-NMR experimentally. The geometry structure optimization, frequencies (IR), NMR, electronic character, frontier molecular orbital (HOMO-LUMO) and first static hyperpolarizability (βtot) studies...

We present the first analytic calculations of the geometrical gradients of the first hyperpolarizability tensors at the density-functional theory (DFT) level. We use the analytically calculated hyperpolarizability gradients to explore the importance of electron correlation effects, as described by DFT, on hyper-Raman spectra. In particular, we calculate the hyper-Raman spectra of the all-trans ...