Cauvery College for Women

Tiruchirappalli, India

Cauvery College for Women

Tiruchirappalli, India
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FTIR, FT-Raman, UV, NMR and quantum chemical calculation studies are performed on 5-chloro-2-nitroanisole, in order to gain the insights of its structural, spectroscopic and electronic properties (Fukui indices, HOMO and LUMO energy gap, MESP and Global reactivity descriptors). A complete vibrational analysis of 5-chloro-2-nitroanisole is performed by HF/B3LYP methods using 6-31G(d,p) basis set. To estimate the electronic transitions, the UV spectra of title compound are predicted in gas phase and ethanol. The obtained absorption maxima at 389.94 nm (in ethanol) is predicted possibly due to HOMO→LUMO transition with 85% contribution and assigned as π-π*. The MESP map shows that the negative potential sites are localized on oxygen atom (O10) as well as the positive potential sites are identified around the hydrogen and ring carbon atoms. The analysis of Fukui indices is also carried out to distinguish the nucleophilic and electrophiic centers. The prediction of reactive sites by MESP is well supported by this Fukui indices analysis. The correlations between the statistical thermodynamics and temperature are also obtained. It is seen that the heat capacities, entropies and enthalpies increase with increasing the intensities of the molecular vibrations. Furthermore, the first hyperpolarizability of 5-chloro-2-nitroanisole is calculated and the results are discussed. This result indicates that 5-chloro-2-nitroanisole is a good candidate of nonlinear optical materials. © 2016 Elsevier B.V.


Arivazhagan M.,Aa Government Arts College | Anitha Rexalin D.,Cauvery College for Women
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

The FT-IR and FT-Raman vibrational spectra of ninhydrin have been recorded in the range 4000-400 cm-1and 3600-50 cm-1, respectively. A detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The optimized molecular geometry, vibrational frequencies, atomic charges, dipole moment, rotational constants and several thermodynamic parameters in the ground state are calculated using ab initio HF and density functional B3LYP methods with 6-311++G(d,p) basis set combination. In order to find the most optimized geometry, the energy calculations are carried out for various possible conformers. Keto and enol forms of ninhydrin are also studied. The condensed summary of the principal NBOs shows the occupancy, orbital energy and the qualitative pattern of delocalization interactions of ninhydrin. The calculated HOMO-LUMO energies reveal that charge transfer occurs within the molecule. The predicted first hyperpolarizability also shows that the ninhydrin molecule have good optical quality and nonlinear optical (NLO) behavior. With the help of specific scaling procedures, the observed vibrational wave numbers in FT-IR and FT-Raman spectra are analyzed and assigned to different normal modes of the molecule. © 2012 Elsevier B.V. All rights reserved.


The vibrational wavenumber of 5-nitro-1,3-benzodioxole (NBD) are obtained and the complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes. The results are compared with experimental frequencies that are obtained from FT-IR and FT-Raman spectra. The NBO analysis of NBD is carried out, which showed the effective energy interaction between the nitrogen lone pair oxygen atom and the sigma antibonding orbitals of the N-O bond. The chemical shifts of the hydrogen and carbon atoms of NBD are determined with the help of computed 1H and 13C NMR spectra. Non-linear optical behaviour is also investigated by the determination of the first hyperpolarizability. This result indicates that NBD is a good candidature for NLO study. In order to analyse the light harvesting efficiency of NBD, donor and acceptor groups are introduced in it as the substituents. All the systems that are designed theoretically in this study are highly red shifted as compared to NBD due to the donor and acceptor substituents. Hence the better dye sensitized solar cell (DSSC) efficiency on the NBD is distinguished in these calculations. However further chemical modification of NBD, such as adding highly effective electron acceptors and donors, is suggested, which could raise the light harvesting efficiency (LHE) of the DSSC. © 2016 The Royal Society of Chemistry.


A complete vibrational and molecular structure analysis is performed based on the quantum mechanical approach by HF and DFT calculations. On the basis of the calculated and experimental results the assignments of the fundamental frequencies are examined. The available experimental results are compared with the theoretical data. A low value of HOMO LUMO energy gap suggests the possibility of intramolecular charge transfer in the molecule. This plays an important role in the significant increase of the β value, which is a property to exhibit nonlinear optical (NLO) activity. The NBO result reflects the charge transfer mainly due to lone pairs. Theoretical 1H and 13C chemical shift values (with respect to TMS) are reported and compared with experimental data which shows the agreement for both 1H and 13C. Predicted electronic absorption spectra from TD-DFT calculations are analysed and they are mainly derived from the contribution of the π → π∗ band. The predicted NLO properties are much greater than those of urea. © The Royal Society of Chemistry 2016.


Arivazhagan M.,Aa Government Arts College | Anitha Rexalin D.,Cauvery College for Women
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectra of 4-chloro-2-fluoroaniline (CFA) have been recorded and analyzed. The equilibrium geometry, bonding features and harmonic vibrational frequencies have been investigated with the help of ab initio and density functional theory (DFT) methods. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule are calculated by the Gauge including atomic orbital (GIAO) method. The first order hyperpolarizability (β0) of this novel molecular system and related properties (β, α0 and Δα) of CFA are calculated using B3LYP/6-311++G(d,p) and HF/6-311++G(d,p) methods on the finite-field approach. The calculated results also show that the CFA molecule might have microscopic nonlinear optical (NLO) behavior with non-zero values. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The result confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The HOMO-LUMO energies UV-vis spectral analysis and MEP are performed by B3LYP/6-311++G(d,p) approach. A detailed interpretation of the infrared and Raman spectra of CFA is also reported based on total energy distribution (TED). The difference between the observed and scaled wave number values of the most of the fundamentals is very small. © 2012 Elsevier B.V. All rights reserved.


Arivazhagan M.,Aa Government Arts College | Meenakshi R.,Cauvery College for Women
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

In the present work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of 4-bromo-o-xylene (BOX). The FT-IR (400-4000 cm -1) and FT-Raman spectra (50-3500 cm -1) of BOX were recorded. The molecular geometry, harmonic vibrational frequencies and bonding features of BOX in the ground state have been calculated by using the density functional B3LYP method with 6-311++G(d,p)/6-311+G(d,p) higher basis sets. The energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT). To determine conformational flexibility, molecular energy profile of BOX was obtained by B3LYP method with 6-311++G(d,p) basis set with respect to selected degree of torsional freedom, which gives three stable conformers. Besides, molecular electrostatic potential (MEP), non-linear properties and NMR analysis were performed at DFT level of theory. © 2012 Elsevier B.V. All rights reserved.


Gayathri R.,Cauvery College for Women | Arivazhagan M.,Aa Government Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

Vibrational spectral measurements, namely, FT-infrared (4000-400 cm -1) and FT-Raman (3500-50 cm -1) spectra have been made for 1,3-dichloro 5-nitrobenzene (DCNB) and assigned to different normal modes of the molecule. Optimized geometrical structure, harmonic vibrational frequencies, intensities, Mulliken's net charges and several thermodynamic parameters in the ground state have been computed by the B3LYP, density functional method using 6-311+G(d,p),6-311++G(d,p) basis sets. Complete assignments of the observed spectra have been proposed. Most of the modes have wave numbers in the expected range. Coupling of vibrations has been determined by calculating total energy distributions (TED) with the help of specific scaling procedures. The calculated HOMO and LUMO energies and electrostatic potential shows that charge transfer occurs within the molecule. The results of the calculations were applied to simulated infrared and Raman spectra of the title compound which showed excellent agreement with the observed spectra. © 2011 Elsevier B.V. All Rights Reserved.


Arivazhagan M.,Aa Government Arts College | Anitha Rexalin D.,Cauvery College for Women
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

In this work, the experimental and theoretical vibrational spectra of 1-bromonaphthalene (1-BN) were studied. FTIR and FT Raman spectra were recorded in the region 4000-400 cm -1 and 3500-50 cm -1, respectively. The structural and spectroscopic data of the molecule in the ground state were calculated by using ab initio Hartree-Fock and density functional method (B3LYP) with the 6-311++G(d,p) basis set. The vibrational frequencies were calculated and scaled values were compared with experimental FTIR and FT Raman spectra. The observed and calculated frequencies are found to be in good agreement. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The optimized geometric parameters were calculated. The predicted first hyperpolarizability also shows that the molecule might have a reasonably good nonlinear optical (NLO) behaviour. The calculated HOMO-LUMO energy gap reveals that charge transfer occurs within the molecule. © 2011 Elsevier B.V.


Arivazhagan M.,Aa Government Arts College | Meenakshi R.,Cauvery College for Women
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

Molecular structure and vibrational frequencies of 1-3-dibromo-5- chlorobenzene (DBCB) have been investigated by density functional theory (DFT) calculations using Becke's three-parameter exchange functional combined with Lee-Yang-Parr correlation (B3LYP) and standard basis set 6-31G. DFT (B3LYP/6-31G) calculations have been performed giving energies, optimized structure, harmonic vibrational frequencies, IR intensities, and Raman activities. Raman and IR spectra of the DBCB were recorded and complete assignment of the observed vibrational bands of DBCB has been proposed. The predicted first-hyperpolarizability of DBCB is 1.221 × 10 -30 esu, which suggests that the title compound is an attractive object for future studies of non-linear optical properties. The impact of di-substituted halogens on the compound has also been discussed. Besides, molecular electrostatic potential (MEP), HOMO-LUMO analysis and NBO analysis were performed at DFT level of theory The UV-vis spectral analysis of DBCB has also been done which confirms the charge transfer of the title compound. © 2011 Elsevier B.V. All rights reserved.


Srinivasan S.,Cauvery College for Women | Ramakrishnan S.,AVVM Sri Pushpam College
Computing | Year: 2013

Cultural algorithms (CA) use social intelligence to solve problems in optimization. The CA is a class of evolutionary computational models inspired from observing the cultural evolutionary process in nature. Cultural algorithms employ a basic set of knowledge sources, each related to knowledge observed in various animal species. Knowledge from these sources is then combined to influence the decisions of the individual agents in solving problems. Classification using "IF-THEN" rules comes under descriptive knowledge discovery in data mining and is the most sought out by users since they represent highly comprehensible form of knowledge. The rules have certain properties which make them useful forms of actionable knowledge to the users. The rules are evaluated using these properties represented as objective and subjective measures. The rule properties may be conflicting. Hence discovery of rules with specific properties is considered as a multi-objective optimization problem. In the current study an extended cultural algorithm which applies social intelligence in the data mining domain to present users with a set of rules optimized according to user specified metrics is proposed. Preliminary experimental results using benchmark data sets reveal that the algorithm is promising in producing rules with specific properties. © 2012 Springer-Verlag Wien.

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