Computational Physics

The aspirin–perchloric acid complex crystal is grown by the vapor diffusion method for the first time. The colorless needle shaped crystals are obtained after 5 weeks duration. These crystals are characterized by powder XRD, FT–IR, FT–Raman, UV–Visible spectroscopy, SEM and melting point studies to confirm the formation of complex crystal of aspirin –perchloric acid. The powder XRD, FT–IR and FT–Raman studies reveal the presence of perchloric acid with the medicinally important drug of aspirin in the complex form. The UV–Visible spectroscopy study shows that the optical window is found to be reduced in the presence of perchloric acid. But there is no change in the transparency of the both crystal in the visible region. The SEM analysis reveals the complex crystal has the distinct morphology in shape from the pure aspirin crystal. The melting point of complex crystal is found to be 110?C. Finally, these studies conclude that mixing of perchloric acid with aspirin changes the all physico-chemical properties of the pure drug compound of aspirin. The property change of aspirin–perchloric acid complex can be used to improve the medicinal activity of the drug compound in the biological systems.

In this article, we are analysing the arrangements of atoms and charge distribution by using optimized geometry of 2,7-Bis(4-Methoxyphenyl) 9,9-Dipropyl-9H-Flurene (Exalite-389), which has been obtained by DFT study. The solvent effect on the molecular orbitals has been investigated by studying parameters like chemical hardness (?), chemical potential (?) and global electrophilicity (?) of the Exalite–389 molecule in vacuum and solvent medium. These outcomes provide a deep understanding of structure of the molecule and electronic properties in different mediums characteristics for optoelectronic applications.

Wavelet Transform is an emerging tool to solve the problems related to Mathematics, Physics and Engineering. In this paper we review and discuss the advantages of Wavelet transform in comparison of Fourier Transform for the study of signal analysis. Wavelet transforms is the improved version of Fourier Transform. The main difference between them is that wavelets are well localized in both time and frequency domain whereas Fourier Transform is only localized in frequency domain. The discretely sampled form of wavelet transform which is called discrete wavelet transform is used in the study of data compression so that one can modify, encode a source of data in digital form that it occupies fewer bits than the original. This will consume less space on the disk and reduce transmission time when such information is communicated over a distance. Further the Wavelet based data compression technique is applied for the study of compression of various data signals such as image, audio, video, seismic and biomedical signals. In this paper we have reviewed about the data compression technique using wavelet transform in different type of signals.

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments and thermodynamic properties of N-(4-methoxybenzylidene) aniline (N4MBA) have been investigated by using ab initio HF/6-311++G(d,p) and DFT/B3LYP method at 6-311G(d,p) and 6-311++G(d,p) basis sets. The energy and oscillator strength calculated by TD-DFT are in line with experimental findings. Moreover, we have not only simulated HOMO and LUMO, but also determined the energy band gap. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using natural NBO analysis. Besides, Mulliken charges were also calculated. IR and Raman intensities were calculated and TED also has been reported.

In a previous study, the epithermal neutron shape factors (?) determined with the monitor combination 198Au-99Mo- 97Zr- 95Zr by the cadmium covered multimonitor method and the triple monitor 198Au- 97Zr- 95Zr in the cadmium lined irradiation channel of the NIRR-1 were found to have relatively high and more reasonable values of -0.101±0.019 and -0.106±0.014 respectively. In this study, the ? value determined with the triple monitor 198Au-99Mo- 95Zr that was obtained from the monitor combination 198Au-99Mo- 97Zr- 95Zr was found to be -0.114±0.017. The accuracy of the ? determination with the monitor combinations 198Au-99Mo- 97Zr- 95Zr , 198Au- 97Zr- 95Zr and 198Au-99Mo- 95Zr was tested by elemental analysis of the standard reference material NIST 1515 Apple leaves by the ko-ENAA method using Al-0.1% Au thin foil as the single comparator. The concentrations of the elements Sm and Br with high Qo values determined in the NIST 1515 Apple leaves are in good agreement with the certified values. The monitor combination 198Au-99Mo- 97Zr- 95Zr or the three monitors 198Au-99Mo- 95Zr from the monitor set Au+Mo+Zr or only the three monitors 198Au- 97Zr- 95Zr from the monitor set Au+Zr can provide reliable values of ? in the cadmium lined irradiation channel for application of the ko-ENAA method for elemental analysis of samples of materials in the NIRR-1.

Effect of difference molar on the optical properties of Al2O3 samples, prepared samples by Sol-gel method. The optical characteristics of the prepared samples have been investigated by UV/Vis spectrophotometer(min 1240) in the wavelength range (370 – 390 ) nm .The samples have a direct allow electronic transition with optical energy (Eg) the value of 0.1 M sample (Al2O3) obtained was (3.276) eV while for other 0.3 M sample (Al2O3 ) was (3.269) eV. The value of ( Eg) was decreased from (3.276) eV to (3.269) eV. The decreasing of (Eg) related to increasing Aluminum Oxide molar on the samples. The maximum value of (n) is (2.1358) for all samples at the differances wavelength which is agreement with molar of Aluminum Oxide increased for all samples of (Al2O3). The results indicate the sample have good characteristics for optoelectronic applications.

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments and thermodynamic properties of 4-Acetyl-N-(4-methoxybenzylidene)aniline [4A-N-(4MB)A] have been investigated by using ab initio HF/6-311++G(d,p) and DFT/B3LYP method at 6-311G(d,p) and 6-311++G(d,p) basis sets. The energy and oscillator strength calculated by TD-DFT are in line with experimental findings. The 1H and 13C NMR chemical shifts calculations of the 4A-N-(4MB)A molecule were carried out by using HF/6-311++G(d,p) and B3LYP functional with 6-311G(d,p)/6-311++G(d,p) basis set. HOMO and LUMO orbitals have been visualized. The stability of the molecule arising from hyperconjugative interaction and charge delocalization has been analyzed using natural NBO analysis. The minimum energy conformational analysis was carried out with the help of PES scan. Besides, MEP was calculated and Mulliken charges, IR and Raman intensities have also been reported.

The Ab-initio and charge density analysis of Au and thiol substituted Dicyclopentyl-Cyclohexan (DCC) molecular nanowire, was carried out using high level Density Functional Theory (DFT) with the help of LANL2DZ basis set coupled with the Bader’s theory of atoms in molecules . All the studies were carried out in the presence of an applied electric field which is gradually increasing from 0.05–0.26VÅ?1. The effect of the applied electric field on the geometrical and the topological analysis of the molecular wire is thoroughly made and studies were made to charcterise the bonds, especially the terminal bonds, which shows ionic nature. The variation in the dipole moment as a consequence of the polarization caused by the applied EF is thoroughly studied. HOMO-LUMO analysis was carried out to determine the way the molecule interacts with other species which may initiates the conductivity. The I–V characteristics of the molecule have been studied for various applied fields for finding the conducting nature of the molecule-electrode-molecule system. The molecular electrostatic potential surface was plotted over the geometry of the molecule to elucidate the reactivity of the molecule.

The molecular vibrations of 2,6-dimethyl pyridine was investigated by FT-IR and FT-Raman spectroscopies. Normal co-ordinate calculations of 2,6-dimethyl pyridine have been carried out using wilson’s FG matrix mechanism on the basis of General valence Force Field (GVFF) for both in-plane and out-of-plane vibrations. The potential energy constants obtained in this study are refined using numerical methods.

Triphenylphosphine [TPP] used in synthesis of organic and organo metallic compounds is investigated for its fundamental reactive properties by density functional theory [DFT] calculations. Natural bond orbital (NBO) analysis enables in comprehending the stability and charge delocalization in the title molecule. Hirshfeld surface analysis for visually analyzing intermolecular interactions in crystal structures employing surface contours and 2D fingerprint plots has been used to scrutinize molecular shapes. Besides NLO, Frontier molecular orbitals and global reactivity descriptors values are calculated. Molecular electrostatic potential map, Fukui Function, Mulliken atomic charges, natural population analysis, Atomic Polar tensors and Thermodynamic analysis were performed. The solvent effects were investigated for obtained molecular energies, hardness and atomic charge distributions were studied for the title compound at TD-DFT method. The binding activity of the molecule with biological targets was examined by docking analysis.