Hawasa University

Hawassa, Ethiopia

Hawasa University

Hawassa, Ethiopia
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Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 2,3-hexadiene have been recorded in the regions 3400-400 and 3400-100 cm -1, respectively. A complete assignment and analysis of the fundamental vibrational modes of the molecule were carried out. The observed fundamental modes have been compared with the harmonic vibrational frequencies computed using HF and DFT (B3LYP, B3PW91) methods by employing 6-31G(d,p) and 6-311++G(d,p) basis sets. The scaled vibrational frequencies are found to coincide with the experimentally observed values. Theoretical infrared and Raman spectra at HF and DFT levels have been constructed and compared with the experimental spectra. A comparative study of computed optimised geometrical parameters, infrared and Raman intensities, thermodynamic values and frequencies obtained by different quantum mechanical methods were presented. Molecular electrostatic potential, total density distribution and frontier orbital energy levels are constructed to understand the electronic properties. The most stable geometry of the compound under investigation has been determined from the potential energy surface scan. © 2011 Elsevier B.V. All Rights Reserved.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Jose S.P.,Madurai Kamaraj University | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

The energy, geometrical parameters and vibrational wavenumbers of crotonaldehyde were calculated by using ab initio and B3LYP with 6-31G(d,p) and 6-311G(d,p) basis sets. The FT-IR and FT-Raman spectra for liquid state crotonaldehyde have been recorded in the region 3400-400 cm -1 and 3400-100 cm -1, respectively and compared with the theoretical spectrographs constructed from the scaled harmonic vibrational frequencies calculated at HF and DFT levels. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. Detailed interpretations on vibrational modes have been made on the observed and theoretical spectra and PED for each mode was also reported more precisely. HOMO and LUMO energy levels are constructed and the corresponding theoretical frontier energy gaps are calculated to realise the charge transfer occurring in the molecule. The thermodynamic properties of the title compound have been calculated at different temperatures and the results reveals the standard heat capacities (C 0 p), standard entropies (S 0) and standard enthalpy changes (ΔH 0) increases with rise in temperature. © 2011 Elsevier B.V.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Rani T.,PRIST University | Mohan S.,Hawasa University
Journal of Molecular Structure | Year: 2011

The FTIR and FT-Raman spectra of 2-(trifluoromethyl)aniline (2TFMA) and 3-(trifluoromethyl)aniline (3TFMA) have been recorded in the range 4000-400 and 4000-100 cm-1, respectively. The experimental vibrational frequencies were assigned and interpreted satisfactorily. The interpretation relies on the theoretical calculations at B3LYP and B3PW91 gradient methods using the standard 6-31G** and higher 6-311++G** basis sets. The frequency calculations were done in ab initio HF method with only 6-311++G** basis set. An extensive study on the vibrational, structural, thermodynamic characteristics as well as the electronic properties of 2TFMA and 3TFMA were carried out using ab initio and DFT methods. In this kind of systems, the position of the substituent group in the benzene ring as well as its electron donor-acceptor capabilities play a very important role on the molecular structural and electronic properties. The influences of the substituents on the structural and electronic properties have been analysed. The intramolecular hydrogen bonds responsible for many features of 2TFMA were analysed. The 1H and 13C FTNMR spectra have been recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. UV-visible spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. © 2011 Elsevier B.V. All rights reserved.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Ravindran P.,PRIST University | Rani T.,PRIST University | Mohan S.,Hawasa University
Journal of Molecular Structure | Year: 2011

The Fourier transform infrared (FTIR) and FT-Raman spectra of 8-chloroquinoline (8CQ) and 8-nitroquinoline (8NQ) have been recorded in the range 4000-400 and 4000-100 cm-1, respectively. The complete vibrational assignment and analysis of the fundamental modes of the compounds were carried out using the observed FTIR and FT-Raman data. Ab initio and DFT calculations have been performed and the structural parameters of the compounds are determined from the optimized geometries with 6-31G**, 6-311++G** and cc-pVTZ basis sets. 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. Uv-visible spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The geometric parameters, energies, harmonic vibrational frequencies, IR intensities, Raman activities chemical shifts and absorption wavelengths were compared with the experimental data of the molecule. The influence of chloro and nitro groups on the skeletal modes and on the proton chemical shifts have been investigated. © 2010 Elsevier B.V. All rights reserved.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Rani T.,PRIST University | Mythili C.V.,Rani Anna Government College for Women | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

A systematic vibrational spectroscopic assignment and analysis of benzohydrazide (BH) has been carried out by using FTIR and FT-Raman spectral data. The vibrational analysis were aided by electronic structure calculations - ab initio (RHF) and hybrid density functional methods (B3LYP and B3PW91) performed with 6-31G(d,p) and 6-311++G(d,p) basis sets. Molecular equilibrium geometries, electronic energies, IR intensities, harmonic vibrational frequencies, depolarization ratios and Raman activities have been computed. Potential energy distribution (PED) and normal mode analysis have also been performed. The assignments proposed based on the experimental IR and Raman spectra have been reviewed and complete assignment of the observed spectra have been proposed. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λmax were determined by time-dependent DFT (TD-DFT) method. The geometrical, thermodynamical parameters and absorption wavelengths were compared with the experimental data. The interactions of carbonyl and hydrazide groups on the benzene ring skeletal modes were investigated. © 2011 Elsevier B.V. All rights reserved.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Kalaivani M.,Kanchi Mamunivar Center for Post Graduate Studies | Ravindran P.,PRIST University | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

The Fourier transform infrared (FTIR) and FT-Raman spectra of 5-chloro-2-hydroxybenzamide (5CBA) and 5-chloro-2-hydroxybenzoic acid (5C2HBA) have been recorded in the range 4000-400 and 4000-100 cm -1, respectively. The complete vibrational fundamental modes of the compounds were assigned and analysed using the observed FTIR and FT-Raman data. The vibrational frequencies determined experimentally were compared with the theoretical wavenumbers calculated from ab initio HF and DFT-B3LYP gradient methods employing 6-31G** and 6-311++G** basis sets. The effect of halogen, hydroxyl groups and hydrogen bonding on the characteristic frequencies of the -COOH and -CONH 2 group frequencies have been investigated. In 5CBA and 5C2HBA intramolecular hydrogen bond between a hydroxyl group and CO group makes a six membered ring, which causes the O⋯H interaction onto the resonance of the benzene ring. Comparison of the positions of the ν(OH) bands shows the ν(OH) band of 5CBA is located at considerably higher frequency which confirms a weaker hydrogen bond than in 5C2HBA. © 2011 Elsevier B.V. All rights reserved.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Balamourougane P.S.,PRIST University | Mythili C.V.,Rani Anna Government College for Women | Mohan S.,Hawasa University
Journal of Molecular Structure | Year: 2011

The solid phase FTIR and FT-Raman spectra of 2-amino-5-chlorobenzoxazole have been recorded in the regions 4000-400 and 3500-100 cm-1, respectively. The spectra were interpreted in terms of fundamentals modes, combination and overtone bands. The normal coordinate analysis was carried out to confirm the precision of the assignments. The structure of the compound was optimised and the structural characteristics were determined by density functional theory (DFT) using B3LYP method with 6-31G(d,p), 6-311++G(d,p) and cc-pVDZ basis sets. The molecular properties were also determined by HF/6-311++G(d,p) level. The vibrational frequencies were calculated in all these methods and were compared with the experimental frequencies which yield good agreement between observed and calculated frequencies. The infrared and Raman spectra were also predicted from the calculated intensities. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-Visible spectrum of the compound was recorded and the electronic properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. The geometric parameters, energies, harmonic vibrational frequencies, IR intensities, Raman activities chemical shifts and absorption wavelengths were compared with the available experimental data of the molecule. The influences of chlorine atom and the amino group on the skeletal modes and on the proton chemical shifts have been investigated. © 2011 Elsevier B.V. All rights reserved.


Tesso T.,Kansas State University | Tirfessa A.,Ethiopian Institute of Agricultural Research | Mohammed H.,Hawasa University
Hereditas | Year: 2011

The Ethio-Sudan region is recognized as the center of origin and diversity for cultivated sorghum. All major races of the crop are widely grown in Ethiopia with durras being dominant. The objective of the present study was to determine the extent of morphological variability among the Ethiopian durras and examine the pattern of relationships among these traits and their association with yield and yield components. Two hundred accessions collected from major sorghum-growing regions of the country were evaluated during the 2007 season at two locations representing hot and dry low land and mild mid-altitude environments. A randomized complete block design with three replications was used. Data were collected on phenology, plant height, a range of leaf traits and yield components. Significant variation was observed among all traits measured. Phenological traits and plant height were significantly correlated with each other and with all leaf traits. There was positive correlation among leaf traits, and between leaf traits and yield components except thousand kernel weight (TKW) and panicle length (PL). Grain fill duration was negatively correlated with all traits except days to maturity, TKW, and leaf length. Yield components except PL and TKW were positively correlated with each other. Selection that focuses on key yield components, larger leaf area, and on enhancing the grain filling rate by reducing excessive grain fill duration may contribute to yield improvement. © 2011 The Authors.


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Mythili C.V.,Rani Anna Government College for Women | Mageswari K.,Kanchi Mamunivar Center for Post Graduate Studies | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

The FT-IR (4000-400 cm-1) and FT-Raman (4000-100 cm -1) spectral measurements of benzamide oxime and complete assignments of the observed spectra have been proposed. Ab initio and DFT calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies, depolarization ratios, IR intensities, Raman activities and atomic displacements. Furthermore, force field calculations have been performed by normal coordinate analysis. Force field calculations showed that several normal modes are mixed in terms of the internal coordinates. A complete assignment of the observed spectra, based on spectral correlations, electronic structure calculations and normal coordinate analysis, has been provided. © 2010 Elsevier B.V. All rights reserved.


Ramalingam S.,Avc College Autonomous | Periandy S.,Tagore Arts College | Mohan S.,Hawasa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

The FTIR and FTRaman spectra of 2-amino pyridine (2-AP) molecule have been recorded using Bruker IFS 66 V spectrometer in the range of 4000-100 cm -1. The molecular geometry and vibrational frequencies in the ground state are calculated by using the ab initio Hartree-Fock (HF) and DFT (B3LYP and B3PW91) methods with 6-31++G (d, p) and 6-311++G (d, p) basis sets. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. Making use of the recorded data, the complete vibrational assignments are made and analysis of the observed fundamental bands of molecule is carried out. The geometries and normal modes of vibrations obtained from ab initio HF and B3LYP/B3PW91 calculations are in good agreement with the experimentally observed data. The differences between the observed and scaled wave number values of most of the fundamentals are very small in B3LYP than HF. The influence of N atom and amine group in the skeletal ring vibrations of the title molecule has also been discussed. Crown Copyright © 2010 Published by Elsevier B.V. All rights reserved.

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