Spectral and Nonlinear Properties of Coconut Oil

In this research, the spectral properties of Absorption and Fluorescence of synthetic coconut oil (Local made) have been studied. It was found that the efficiency of coconut oil equal to (3.276%). In addition, non-linear optical properties represented by the refractive index (n2) and absorption coefficient(β) have been calculatal using three –dimensioual scanning technigue (z-scan and Helium Neom laser. Refractive inex (n2=4.231×10-7 cm2/mW) and absorption coefficient (β= 0.72373 cm/mW) have been measured from Closed-aperture part and Open-aperture part, respectively. Coconut oil has non-linear properties, where it can be utilize in nonlinear spectral applications, especially in the study the living tissue through its application and its treatment with laser.

Two-step Brillouin zone sampling for efficient computation of electron dynamics in solids

We develop a numerical Brillouin-zone integration scheme for real-time propagation of electronic systems with time-dependent density functional theory. This scheme is based on the decomposition of a large simulation into a set of small independent simulations. The performance of the decomposition scheme is examined in both linear and nonlinear regimes by computing the linear optical properties of bulk silicon and high-order harmonic generation. The decomposition of a large simulation into a set of independent simulations can improve the efficiency of parallel computation by reducing communication and synchronization overhead and enhancing the portability of simulations across a relatively small cluster machine.

Density Functional Theory Investigation of the Doping Effects of Bromine and Fluorine on the Electronic and Optical Properties of Neutral and Ionic Perylene

Perylene and its derivatives are some of the promising organic semiconductors. They have found vast applications in many areas such as photovoltaic systems, organic light-emitting diodes, and so on. The instability of organic molecules under ambient conditions is one factor deterring the commercialization of organic semiconductor devices. Currently, most of the investigation of Perylene and its derivatives concentrated on its diimide and bisimide derivatives. In this work, an investigation of the effects of doping Bromine and Fluorine on the electronic and non-linear optical properties was carried out based on Density Functional Theory (DFT) as implemented in the Gaussian 09 software package. We computed the Molecular geometries of the molecules, HOMO-LUMO energy gap, global chemical indices and non-linear optical properties using the same method. The bond lengths and angles of the mono-halogenated molecules at different charge states were found to be less than that of the isolated Perylene. 1-fluoroperylene was found to be the most stable amongst the studied molecule for having the least bond angles and bond lengths. In the calculation of the energy bandgap neutral 1-fluoroperylene was observed to have the highest energy gap 3.0414 eV and 3.0507 eV for 6-31++G(d,p) and 6-311++G(d,p) basis sets respectively. These results were found to agree with the existing literature. This reconfirmed 1-fluoroperylene as the most stable molecule. The computations of the ionic molecules reported small values of the energy gap. The molecule with the most chemical hardness was obtained to be the neutral 1-fluoroperylene with a chemical hardness of 1.5253eV. All the ionic molecules results were found to be more reactive than their neutral form for having lower values of chemical hardness. For NLO calculations, the results showed an increment in their values with the ionic hybrid molecules having the largest values. In the case of first-order hyper-polarizability, 1-bromoperylene (neutral), 1-fluoroperylene (neutral), 1-bromoperylene (anionic), 1-fluoroperylene (anionic), 1-bromoperylene (cationic) and 1-fluoroperylene (cationic) were found to be 73.93%, 1.71%, 83.9%, 39.2%,38.7% and 41.7% larger than that of Urea respectively. These calculated results make these hybrid molecules suitable for a wide range of optoelectronic applications.

Linear optical properties of HKUST-1 metal-organic framework: Effect of the crystal size and synthetic approach

We evaluated the change in the transmission and reflection spectra of single rhombic dodecahedron nanocrystals of the metal organic frameworks HKUST-1 with and without effect of near infrared laser radiation. The analysis of commercial and synthesized in the laboratory compounds was made through the optical transmittance and reflectance spectroscopy. Moreover, electronic microscopy and light scattering on the microcrystals was also utilized for revealing the size dependent colour. Such studies may find new application for MOF nanocrystals, as well as gain additional information about their usage for biological purposes or in computer sensing.