ASIAN JOURNAL OF PHYSICS

Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 201-230

Spectra and structure of benzonitriles and some of its simple derivatives

M Alcolea Palafox¹  and V K Rastogi²

¹Departamento de Química-Física-I, Facultad C Químicas UCM, Madrid-28040, Spain

²R D Foundation Group of College, NH-58, Kadrabad, Modinagar (Ghaziabad), India

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Dedicated to Professor KPR Nair

This chapter shows a short compendium of the structure and spectra of Benzonitrile and some of its simple mono- and di-substituted derivatives, with special attention on those with important properties. The importance and main applications of these molecules are also briefly indicated. The geometry and vibrational wavenumbers are analyzed. Several correlations with the structure and spectral parameters are exposed.

Keywords: Benzonitrile, benzonitrile derivatives, molecular structure, vibrational wavenumbers,ab initio methods.

Total Refs: 171

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 231-248

 

Photoacoustic spectroscopy of chemical vapours and atmospheric pollutants

 

Surya N Thakur

Ex-Professor of Physics, Banaras Hindu University, Varanasi-221 005, India

 

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Dedicated to Professor KPR Nair

The review article starts with the basic principles of photoacoustic spectroscopy and describes in detail the methods of recording spectra using a microphone, a quartz tuning fork and a probe laser. The latest developments in this field using quantum cascade laser sources and very compact photoacoustic cells used by leading researchers have been described.  Examples of trace gas detection include atmospheric pollutants and aerosols; horticultural damaging gases and medically important molecules.

Total Refs: 48

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 249-258

 

Quantum fluctuations of the radiation field and wave particle duality

 

H Konwar¹ and G D Baruah^{1, 2}

¹Department of Physics, Dibrugarh University, Dibrugarh-786 004 (India)

^{1, 2}Center for Laser and Optical Science, New Uchamati, Doom-Dooma-786 151 (India)

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Dedicated to Professor KPR Nair

Zero point fluctuation or vacuum fluctuation is the straightforward consequence of quantized radiation field. All quantized fields have fluctuations even in the vacuum state. Vacuum is not a tranquil state of nothingness, but rather a quantum state with fluctuations called vacuum fluctuations endowed with physical consequences. Vacuum fluctuations hold the key to understanding several processes including Lamb shift, spontaneous emission, Casimir effect and laser line width.In the present work we have worked out a method which indicates that the wave particle duality is the inherent nature of quantum fluctuation of the radiation field.

Keywords: Vacuum fluctuations, zero point energy, quantized field, wave particle duality, number state, vacuum state.

Total Refs: 36

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 259-262

 

Multiconfiguration Hartree-Fock calculations in the sodium sequence

 

S N Tiwary

University Department of Physics, BRA Bihar University, Muzaffarpur, (Bihar), India

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Dedicated to Professor KPR Nair

Excitation energies (∆E) and optical oscillator strengths (OOS), of both length ( fL) and velocity ( fV) forms, have been calculated for the inner-shell excitation 1s² 2s² 2p⁶ 3s ²S^e → 1s² 2s² 2p⁵ 3s²²P^o transition, which leads to auto ionization (Auger transition), in Mg⁺, Al²⁺, Si³⁺, P⁴⁺, S⁵⁺, Cl⁶⁺, Ar⁷⁺ and K⁸⁺ ions of the sodium isoelectronic sequence by employing multi configuration Hartree-Fock (MCHF) method exactly in the same way as we did in our earlier work (Tiwary et al, Pramana-J. Phys. 46, 381 (1996); Kumar, Tiwary and Ray, Pramana-J. Phys. 76, 1 (2011)). Comparison has been made with our earlier theoretical results obtained by using the Hartree-Fock (HF) and the configuration interaction (CI) methods (Tiwary et al, Fizika 23, 27(1991)). Our present MCHF result is encouraging. © Anita Publications. All rights are reserved.

Keywords: Ions, Excitation energies; Oscillator strengths; MCHF.PACS No.: 31.20

Total Refs : 24

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 263-270

Optical properties of sodium salicylate as a wavelength  shifter under the effect of synchrotron radiation

 

Vijay Kumar^a, B N Raja Sekharb*, V N Rai^c, Param Jeet Singh^b, V Sivasubramani ^d and, S K Deb^c and B N Jagatap^b

^aIndus Operation & Accelerator Physics Design Division, RRCAT, Indore-452 013, India

^bAtomic and Molecular Physics Division, BARC, Trombay, Mumbai-400 085, India

^cIndus Synchrotron Utilization Division, RRCAT, Indore-452 013, India

^dMaterial Science Division, IGCAR-Kalpakkam-603 102, India

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Dedicated to Professor KPR Nair

Optical properties of sodium salicylate coating used as wavelength shifter in photophysics beamline at Indus-1 are presented. The absorption as well as photoluminescence of the coating decrease under the effect VUV irradiation and aging. Irradiation as well as aging produces different types of structural changes in the coating. VUV irradiation induces photochemical reaction resulting in some other compound and/or some defects, which drastically changes optical and structural properties of the coatings.

Keywords: Vacuum ultraviolet detector, Wavelength shifter, Absorption and photoluminescence,UV-Visible spectroscopy, Infrared and Raman spectroscopy

PACS: 41.60.Ap, 42.70.–a, 61.72.–y, 61.80.–x, 78.20.–e

Total Refs: 24

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 271-276

Polarizability, hyperpolarizability, optical gap and hardness of halogenated aniline derivatives – A comparative study using conventional and  long-range corrected hybrid functional

V Balachandran^a*, K Anitha^b and M Karunanidhi^c

^aCentre for Research, Department of Physics, A A Government Arts College, Musiri, Tiruchirapalli-621 201, India

^bDepartment of Physics, Bharathidasan University Constituent College Lalgudi, Tiruchirapalli-621 601, India

^cDepartment of Physics, Srimad Andavan Arts & Science College, Tiruchirapalli-620 005, India 

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Dedicated to Professor KPR Nair

Calculations at Hatree-Fock(HF), Density Functional Theory (DFT) and Long range Correction (LC-DFT) functional were carried out with 6-311++G(d,p) basis set for estimate the dipole moment (µ), the static polarizability (α), second hyperpolarizability  (β), optical gap  (∆H-L) and chemical hardness  (η) of halogenated aniline derivatives. Variations in optical gap and first hyperpolarizability which are measures of non-linear optical parameters are also computed. Our  results show that DFT schemes overestimate a values relative to LC-DFT ones. The average dipole moment  (µ),  the static polarizability (α),  second hyperpolarizability  (β),  optical gap  (∆H-L) and chemical hardness  (η) of halogenated aniline derivatives show their optimum value for 2-bromoaniline, 2-chloroaniline, and 2-fluoroaniline derivatives. The maximum polarizability and minimum chemical hardness are due to greater extents of charge transfer which arise from smaller optical gap. The study reveals that the halogenated aniline based molecules are promising candidates for applications in non-linear optics.

Keywords: Hyperpolarizability, Optical gap, Long range correction, Aniline derivatives.

Total Refs : 22

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 277-290

FT-IR and FT-Raman spectral analysis and quantum chemical studies on 4-aminobenzoic acid

and 4-cyanobenzoic acid

V Arjunan^1*, R Remya², L Devi², S Senthikumari¹ and S Mohan³

¹Department of Chemistry, Kanchi Mamunivar Centre for Post-Graduate Studies, Puducherry-605 008. India

²Research and Development Centre, Bharathiar University, Coimbatore 641 046, India

³School of Sciences and Humanities, Vel Tech University, Avadi, Chennai-600 032

____________________________________________________________________________________________________________________________________ Dedicated to Professor KPR Nair

The FT-IR and FT-Raman spectra of 4-aminobenzoic acid (4ABA) and 4-cyanobenzoic acid (4CBA) 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. The vibrational frequencies determined experimentally were compared with those obtained theoretically from ab initio HF and DFT-B3LYP gradient calculations employing 6-31G**, 6-311++G** and cc-PVTZ basis sets for the optimised geometries of the compounds. The normal coordinate analysis was also carried out by Wilson’s FG matrix method. The interactions of the skeletal vibrational modes are investigated.© Anita Publications.

Keywords: 4-aminobenzoic acid, 4-cyanobenzoic acid, DFT, FTIR, FT-Raman.

Total Refs : 53

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 291-304

Spectroscopic and DFT studies of 2, 3-dihydro-4-methylthiophene-1, 1-dioxide

and 2,3-dihydrothiophene-1, 1-dioxide

V Arjunan^1*, R Remya², R Anitha¹, Arushma Raj¹ and S Mohan³

¹Department of Chemistry, Kanchi Mamunivar Centre for Post-Graduate Studies, Puducherry-605 008, India

²Research and Development Centre, Bharathiar University, Coimbatore-641 046, India

³School Sciences and Humanities, Vel Tech University, Chennai-600 062, India

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Dedicated to Professor KPR Nair

Spectroscopic studies and theoretical quantum chemical calculations of 2,3-dihydro-4-methylthiophene-1,1-dioxide (DHMT) and 2,3-dihydrothiophene-1,1-dioxide (DHT) have been carried out by using B3LYP methods, FTIR and FT-Raman spectral techniques. The geometry of the compounds have been optimized by B3LYP method with 6–311++G** and cc–pVTZ basis sets. The geometrical parameters obtained at B3LYP levels have been compared with the experimental values. Molecular electrostatic potential surface, total electron density distribution and frontier molecular orbitals are constructed at B3LYP/cc–pVTZ level to understand the electronic properties. The charge density distribution and site of chemical reactivity of the molecules have been obtained by mapping electron density isosurface with electrostatic potential surfaces. The HOMO and LUMO energies and their energy gap are measured.

Keywords: 2, 3-dihydro-4-methylthiophene-1,1-dioxide, 2, 3-dihydrothiophene-1, 1-dioxide, B3LYP, FTIR, FT-Raman.

Total Refs : 35

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Asian Journal of Physics                                                                                                       Vol. 22, No. 3 (2013) 305-312

DFT and vibrational spectroscopic study on glycinium  succinimide NLO active material

 

D Arul Dhas^a, I Hubert Joe^b, S D D Roy^a and S Balachandran^c

^aDepartment of Physics, Nesamony Memorial Christian College, Marthandam-629 165, TamilNadu India

^bCentre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College,   Thiruvananthapuram-695 015, Kerala, India

^cDepartment of Chemistry, M G College, Thiruvananthapuram-695 004, Kerala, India

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Dedicated to Professor KPR Nair

Vibrational spectral analysis of glycinium succinimide have been carried out using NIR FT-Raman and FTIR spectroscopic techniques. The FTIR and FT-Raman spectra have been recorded in the region 400–4000 cm^-1 and 50-3500 cm^-1 respectively. The geometry has been optimized with complete relaxation on the potential energy surface at B3LYP level of theories using 6-311G (df, p) basis set using Gaussian 09 program and compared with the crystal data. Further harmonic vibrational frequency calculations have been carried out at B3LYP levels and the scaled values were in good agreement with majority of the experimental observations. The NBO and structural analysis have been performed. Theoretical methods have been used to study the proper and improper hydrogen bonds, considering the hydrogen bond length and charge transfer. The calculated geometrical parameters also show a very strong hydrogen bond. The first order hyperpolariz and charge transfer analysis shows the NLO active nature of the experimental compound.

Keywords: DFT, Hydrogen bonding, NLO activity, NBO analysis, FTIR, FT-RAMAN.

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