000047   Kneipp K;Kneipp H;Dasari R R;Feld M S (NO, Massachusetts Insititute of Technology, Cambridge MA-02139, USA) : Single molecule Raman spectroscopy using silver and gold nanoparticle. Indian J Phys-Pt B 2003, 77(1), 39-47.

Gives a brief introduction to single molecule SERS spectroscopy, describes nonresonant single molecule Raman experiments at near infrared excitation and discuss prospects and limitations of the method.

8 tables, 37 ref

000046   Kartha V B;Jyothi Lakshmi R;Mahato K K; Krishna C;Santhosh C;Venkata Krishna K (Centre for Laser Spectroscopy Dep, Manipal Academy of Higher Education, Manipal) : Raman spectroscopy in clinical investigation. Indian J Phys-Pt B 2003, 77(1), 113-23.

Raman spectroscopy has been successfully applied in several areas of biology and medicine, including diagnosis of malignancy. The applications of Surface Enhanced Raman spectroscopy and micro-Raman have improved to the extend of studying single mlecule dynamics and the cellular biochemistry respectively. Raman spectroscopy studies carried out in laboratory on oral cancer, osteoradionecrosis, radiation induced damages in mouse models are presented and discussed. Records Raman spectra of normal and malignant oral tissues and the obtained spectra were analysed using statistical (PCA) methods. An objective diagnosis method with high sensitivity and specificity based on Mahalanobis distance and spectral residual is developed for oral malignancy. The study of radiation induced damdage in mouse brain and muscle tissue suggests that radiation activated chemical cascade is similar to those in stress, but it persists for longer periods. Radiation treatment on bone leads to immediate structural changes in the mineral part of the bone.

15 illus, 39 ref

000045   Kalyanaraman S B;Vasantharani P;Selvakumari P (Department of Physics, Annamalai University, Annamalainagar, Tamil Nadu-608 002) : Computation of excess values of some acoustical parameters of binary/ternary liquid systems using C-program. Indian J pure appl Phys 2003, 41(5), 346-9.

Excess values of acoustical parameters obtained from experimental measurements and theoretical calculations in binary.ternary liquid mixtures provide valuable information about the nature and strength of molecular interactions in the system. A brief explanation on the computation of the excess values of acoustical parameters using C-program is presented.

2 tables, 4 ref

000044   Kalaivani T;Kumar S;Krishnan S (Department of Physics, Annamalai University, Annamalainagar-608 002) : Dielectric relaxation study of some binary liquid mixtures using frequency domain technique. Indian J pure appl Phys 2003, 41(5), 398-401.

Dielectric relaxation studies have been carried out in three binary systems namely hexanol, heptanol and octanol with benzene solution. The oscillating frequency of X-band microwave bench is at 9.36 GHz. The orientation of molecular dipoles have been identified by the Kirkwood linear correlation factor (g). The relaxation time (τ) is obtained by both Higasi's and Cole-Cole method. The dipole moments of the systems are determined by Higasi's and Gopalakrishan's method. The activation energies due to the relaxation process (ΔFτ) and the viscous flow (ΔFτ) are calculated.

1 illus, 1 table, 15 ref

000043   Jatkar D P (NO, Harish Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad-211 019]) : Brane world scenarios. Pramana J Phys 2003, 60(2), 183-8.

Reviews proposals of brane world models which attempt to combine gauge theories with gravity at TeV scale by confining the gauge theory to a three-brane embedded in higher dimensional bulk. Gravity, however, propagates in the directions transverse to the brane as well.

1 illus, 6 ref

000042   Huitu K (NO, Helsinki Institute of Physics, Finland) : Phenomenology of radions. Pramana J Phys 2003, 60(2), 209-14.

Discusses the phenomenology of radion of the Randall-Sundrum type models, considers radion couplings and its production and decay, in the same time taking into account the mixing of radion with Higgs.

17 ref

000041   Goswami S (NO, Harish Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad-211 019) : Progress in neutrino oscillation searches and their implications. Pramana J Phys 2003, 60(2), 261-78.

Neutrino oscillation, in which a givben flavor of neutrino transforms into another is a powerful tool for probing small neutrino masses. The intrinsic neutrino properties involved are neutrino mass squared difference Δm² and the mixing angle in vaccum θ. Summarizes the progress in search for neutrino oscillation with special emphasis on the recent results from the Sudbury Neutrino Observatory (SNO) on the measurement of solar neutrino fluxes. Outlines the current bounds on the neutrino masses and mixing parameters and discuss the major physics goals of future neutrino experiments in the context of the present picture.

4 illus, 4 tables, 4 ref

000040   Gagnani M A;Shukla R;Hari S K;Misra S N (NO, Central Salt & Marine Chemicals Research Institute, Bhavnagar, Gujrat-364 002) : Comparative absorption spectroscopy involving 4f-4f transitions to explore kinetics of complexation of Zn(II) with Er(III)-glutathione complex & compositional dependence of intensity parameters. Indian J pure appl Phys 2003, 41(5), 374-83.

The kinetic and spectroscopic investigations on complexation of Zn(II) with Er₂(GSH)₂(H₂O)₄ 1 (GSH = reduced glutathione) to form Er₂(GSH)₂Zn(H₂O)₆ complex 2 have been performed at 30 °C by following five, 4f-4f sensitive transitions of lanthanide Er(III), ⁴I_15/2 → ⁴IG_11/2, ⁴I_{15/2 → ⁴F7/2, ⁴I15/2 → ²H11/2, ⁴I15/2 → ⁴F9/2 and ⁴I15/2 → ⁴I11/2 in water as well as in equimolar mixture of DMF and water. Performances of all the five bands were found to be completely sensitive, on the basis of kinetic studies done by following the changes in the intensity (absorbance, molar absorptivity)and intensity parameters (oscillator strength P and Judd-Ofelt Tλ intensity). Kinetics showed first order dependence in terms of concentrations of Zn(II) and complex 1 on the rate of formation of complex 2. In order to support the kinetic and spectroscopic observations, complex 1 and 2 were synthesized also, and were characterized by C, H, N, S, and elemental analysis; UV/VIS, NMR and IR techniques. Kinetic, mechanistic and spectroscopic aspects of the complexation reaction are presented and discussed.}

2 illus, 3 tables, 33 ref

000039   Durig J R;Zheng C (Chemistry Dep, University of Missouri-Kansas City, Kansas City, MO 64110-2499 USA) : Raman spectra and infrared spectra; conformational stability, ab initio claculations, and r<. Indian J Phys-Pt B 2003, 77(1), 125-37.

The Raman and/or infrared (3500 to 50 cm^-1) spectra of some gaseous, liquid and solid organo-amines and methyl substituted hydrazines have been recorded. Additionally, variable temperature (-55 to -150°C) infrared studies of several of these molecules dissolved in liquid xenon and/or krypton have been recorded and the enthalpy differences determined for hte moleculed which have conformers present at ambient temperature. Utilizing low frequency spectral data along with the enthalpy differences, the potential functions governing the conformational interchanges have been obtained. The geometric parameters, harmonic force constants, vibrational frequencies, Raman activities and depolarization ratios, infrared intensities, and energy differences, have been obtained from MP2 (full)/6-31G(d) ab initio calculations. Additionally structural parameters and energies have been obtained from MP2(full)/6-31G(d,p) and MP2(full)/6-311G(2d,2p) calculations as well as the corresponding ones with diffuse functions. The predicted quantities are compared to the experimental ones when appropriate. For several of the molecules, the r⁰ structural quantities have obtained by combining ab initio MP2(full)/6-311<43>G(d,p) predicted parameters with previously reported microwave rotational constants.

6 illus, 3 tables, 82 ref

000038   Dresslhaus M S;Dresselhaus G;Rao A M;Jorio A; Souza Filho A G;Samsonidze G C;Saito R (Physics and Electrical Engineering and Computer Science Dep, Massachustts Institute of Technology, Cambridge, MA 02139) : Resonance Raman scattering on one-dimensional system. Indian J Phys-Pt B 2003, 77(1), 75-99.

A review of the resonance Raman effect in one-dimensional (1D) system is presented. Due to the strong electron-phonon coupling and the quantum confinement of electrons and phonons in 1D systems, interesting effects are observed, such as asymmetries in the Stoke/anti-Stokes spectra and line-shape dependence on satisfying the resonance condition. Analysis of these effects give detailed information about the confined phonon and electron states, showing that resonance micro-Raman spectroscopy of phonon modes can determine electronic and structural properties of 1D-systems. The single wall carbon nanotube (SWNT) is used as a prototype iD system for describing resonance Raman scattering in 1D, since many experimental results are now available for this system at single nanotube level, and because detailed theoretical modeling can be carried out for this system. The results on SWNTs should provide a valuable guide for Raman studies on other 1D systems. It is also shown that the resonance Raman effect provides a useful technique for obtaining phonon dispersion relations for nanoscale samples, and that measurements on low dimensional systems can be used to obtain important information about related higher dimesional systems that is otherwise difficult to obtain.

23 illus, 58 ref

000037   Djouadi A (NO, LPMT, Universite de Montpellier II, F-34095 Montpellier Cedex 5, France) : The search for Higgs particles at high-energy colliders: Past, present and future. Pramana J Phys 2003, 60(2), 215-38.

Previews the Higgs sector in the standard model (SM) and its minimal aupersymmetric extension, the MSSM. After summarizing the properties of the Higgs bosons and the present experimental constraints. Discusses the prospects for discovering these particle at the upgraded Tevatron, the large hadron collider (LHC) and a high-energy e⁺e^- linear collider. The possibility of studying the properties of the Higgs particles will be then summarized.

14 illus, 2 tables, 40 ref

000036   Deshpande N G (Institute of Theoritical Science, University of Oregon, Eugene, Oregon 97403-5203, USA) : CP violating rate asymmetries in B decays. Pramana J Phys 2003, 60(2), 353-62.

Briefly discusses measurements of angles β and α of the unitarity triangle. Reviews rate asymmetries using SU(3) relationships in the standard model (SM). Some methods to measure angle γ using SU(3) are then discussed. Note that rate for b→sγ can be used to set limits on extra dimensions in which standard model particles propagate.

2 illus, 1 table, 21 ref

000035   Deshpande N G (Institute of Theoritical Science and Department of Physics, University of Oregon, Eugene, OR 97403-5203, USA) : A review of non-commutative gauge theories. Pramana J Phys 2003, 60(2), 189-98.

Construction of quantum field theory based on operators that are functions of non-commutative space-time operators is reviewed. Examples of φ⁴ theory and QED are then discussed. Problems of extending the theories to SU (N) gauge theories and arbitrary charges in QED are considered. Construction of standard model on non-commutative space is then briefly discussed. The phenomenological implications are then considered. Limits on non-commutativity from atomic physics as well as accelerator experiments are presented.

14 ref

000034   Datta A (Helsinki Institute of Physics, P.O. Box 64, University opf Helsinki, Helsinki, Finland) : Supersymmetry search via gauge Boson fusion. Pramana J Phys 2003, 60(2), 363-8.

Proposes a novel method for the search of supersymmetry, especially for the electroweak gauginos at the large hadron collider (LHC). Gauge boson fusion technique was shown to be useful for heavy and intermediate mass Higgs bosons. Shows that this method can also be applied to find the signals of EW gauginos in supersymmetric theories where the canonical search strategies for these particles fail.

2 illus, 13 ref

000033   Choudhury M G M;Kao J S;Lai G R;Ali G M R (department of Physics, University of Rajshahi, Rajshahi-6205 Bangladesh) : Charaterization of zirconium dioxide thin films prepared by cw CO₂ laser-assisted evaporation. Indian J pure appl Phys 2003, 41(5), 362-8.

Zirconium dioxide thin films have been deposited by cw CO₂ laser-assisted evaporation on Si(100), quartz and optically polished glass substrates at different substrate temperature. Films were growth in oxygen, under partial pressure. The surface morphology of the films has been observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the structure has been studied by X-ray differaction (XRD). The optical bandgap has been calculated from transmission spectra, taken in the UV range. The dc dark conductivity has been investigated in the temperature range 30-130°C. The SEM micrographs show that, the film surfaces are smooth and polycrystalline and grows in a well-aligned columnar structure. XRD observations revealed that, the structure of the films deposited at 250°C substrate temperature is tetragonal having lattice constants a = 0.5074 nm and c = 0.572 nm. The bandgap evaluated from optical spectra is = 5.25 eV. The dc conductivity shows linear variation with temperature with the experimental temperature range, suggesting an activated process, having single activation energy.

5 illus, 1 tables, 16 ref

000032   Choudhary S N;Mahato N K;Prasad K (Physics Dep, T M Bhagalpur University, Bhagalpur-812 007) : Phase transition in Pb[Cu<. Indian J Phys-Pt A 2003, 77(2), 125-8.

Pb[Cu^1/2W^1/2]O³ (PCW) ceramic has been prepared using solid-state reaction method. XRD-studies showed that PCW has a single phase with orthorhombic structure. The density of sample was found to be 93-95% of the theoretical value. Dielectric properties are measured in the frequency range 0.2 kHz to 10 kHz at 26°C and in temperature region 26°C and in temperature region 26°C to 250°C at 1 kHz and 10 kHz. PCW shows successive phase transitions at T^c1 (upper Tc)<61>87° and T^c2 (lower Tc)<61> 50°C at 1 kHz. This successive phase transition is similar to that observed in Pb[Co^1/2W^1/2]O³ earlier. Diffuse phase transition is oberseved with the diffusivity parameter (s), as estimated from Kramer-Kronig relation and was found to be 1.52.

4 illus, 18 ref

000031   Calla O P N;Agarwal S;Agarwalla S K; Bhattacharjee R;Kalita A (NO, International Center for Radio Science, "OM-NIWAS" A-23, Shastri Nagar, Jodhpur-342 003) : Comparitive study of the methods of measurement of dielectric constant at microwave frequencies for dry and wet soil. Indian J Radio Space Phys 2003, 32(2), 108-13.

An attempt has been made to do the comparitive study of the three different methods of measurement of dielectric constant of soil collected from Rajasthan at different gravimetric moisture content. The measurements have been made using waveguide cell, resonant cavity and HP network analyzer at X-band.

3 illus, 3 tables, 4 ref

000030   Brahmachari B;Choubey S;Mohapatra R N (NO, Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700 064) : Sterile neutrino in a minimal three-generation see-saw model. Pramana J Phys 2003, 60(2), 377-81.

Investigates symmetries in Dirac and Majorana mass matrices of neutrons in a three-generation scenario. Shows that if we invoke L_e + Lμ - Lτ x S_2R symmetry, one combination of right-handed neutrino states remains massless which can be interpreted as a sterile neutrino. Considers a SU(2)_L x U(1)_γ x U(1)_R gauge model and show how higher-dimensional operators can induce mixing between left-and right-handed states which explains solar, atmospheric and LSND experimental results.

1 tables, 14 ref

000029   Bose D N;Bandopadhyay A K (USIC Dep, University of Calcutta, 92, A.P.C. Road, Kolkata-700 009) : Semiconductor material characterisation by Raman spectroscopy. Indian J Phys-Pt B 2003, 77(1), 139-43.

Among optical techniques used in the characterization of semiconuductors, Raman Spectroscopy (RS) has emerged as a powerful tool. Its advantages are its versatility and well-developed theory which permits the study of phonons, quantitative determination of carrier concentration, stress and electric field besides identification of impurities and unknown phases. It is complementary to the well-known technique of Photoluminescence (PL) and requires similar equipments. RS has also proved to be the most powerful technique for investigating vibrational excitations in superlattices. Reviews the application of Raman spectroscopy to semiconductor materials characterisation and provides examples from studies on surface passivation of CdTe, ion-implantation of Si donors in GaAs and evaluation of InGaAs / InP quantum wells.

3 illus, 2 tables, 17 ref

000028   Bhattacharya R;Dey S S;Datta T;Bhattacharya A B (Centre for Atmospheric Sciences, University of Calcutta, Kolkata-700 009) : A multilayer fuzzy neural networkapproach for cloud classification. Indian J Radio Space Phys 2003, 32(2), 104-7.

Physical processes affecting cloud detection have been analysed considering both cloud segmentation and cloud labeling in satellite data. Application of neural networks to cloud screening is examined with a special emphasis to cloud segmentation in AVHRR data. Some improved methods for analysing and comparing satellite and surface observations of cloud pattern have been critically discussed. Finally, multilayer perceptron of neural network has been proposed as a possible better model for cloud label classification.

2 illus, 23 ref

000027   Benjamin C;Jayannavar A M (NO, Institute of Physics, Sachivalaya Marg, Bhubaneswar-751 005, Orissa) : Quantum current enhancement effect in hybrid ring at equilibrium. Indian J Phys-Pt A 2003, 77(2), 119-23.

Current enhancement - a novel quantum phenomenon is found to occur in a mesoscopic hybrid ring at equilibrium. The hybrid system is described by a ring with bubble which is in turn coupled to a reservoir. In the system the ring encloses a magnetic flux Ψ while the bubble does not enclse and flux. The novelty of this work lies in the fact that while earlier current enhancement was observed in non-equilibrium systems (e.g., a ring coupled to tow reservoirs at different chemical potentials μ¹ and μ²), herein prove it is that current enhancement can also arise in equilibrium. In addition shows that the closed system analog of oru chosen open hybrid ring system violates parity effects. Finally focus as the discrepancy between the equilibrium magnetic moment (obtained via energy eigenvalues) and that calculated from the currents in the system.

5 illus, 14 ref

000026   Behera D;Dash S K;Mishra N C (Physics Dep, Utkal University, Bhubaneswar-751 004) : Transport characteristics and effect of Ag in controlling thermally activated phase-slip in Ca doped YBa<. Indian J Phys-Pt A 2003, 77(2), 133-8.

DC resistivity of Y^1-xCa^xBa²Cu³O^7-y and Y^1-xCa^xBa²Cu³O^7-X/Ag composite buld sinter samples has been studied as a function of applied magnetic field anmd temperature. A percolative current conduction model was utilized to quantify granularity in the bulk in terms of such parameters like the weak link resistivity across grain boundaries, current path lengthening factor arising due to grain misalignment, and due to voids and cracks. Evolution of these parameters with Ag content in thesample indicates improved grain alignment and reduced structural defects (voids and cracks). The resistive broadening by magnetic field has been described by thermally activated flux creep or fluxflow behaviour which is much reduced in Ag composite sample. Hence the grain boundary which has much technical application is improved by Ag addition.

9 illus, 29 ref

000025   Basuray A;Mukhopadhya S (NO, Neo Tele-Tronix Pvt. Ltd. (NTPL), 6/7, Bijoygarh, Kolkata-700 032) : Study of the effect of magnetic field on the impurity bound polaronic energy level in a parabolic quantum dot. Indian J Phys-Pt A 2003, 77(2), 129-32.

The problem of interface optical poloaron, bound to an impurity atom in a parabolic quantum dot near the semiconductor heterostructure has been investigated in the framework of canonical transformation method. An external magnetic field is applied in the growing direction of the quantum dot heterostructure (along the z-direction). A calculation has been proposed to study the dependence of the ground state energy on the magnetic field and the thickness of the well. The binding energy and hence the quantum confinement increase with the increasing magnetic field. The effect of the thickness on teh induced potential and hence on the ground state energy has also been studied.

2 illus, 9 ref

000024   Banerjee B;Roy S K (Physics Dep, Visva Bharati University, Santiniketan-731 235) : Physics of binding between cell-adhesion molecule (CAMs) in biosample. Indian J Phys-Pt A 2003, 77(2), 187-91.

The binding mechanisms in biological systems which are very useful to explain the pattern formation are discussed on the physics like model of interaction due to CAMs. The morphogenesis of animals is discussed from the analogy of one dimensional systems with interactions equivlent to cell-cell and cell-background interactions in biosamples. Some very intersting comments can be made regarding the color morphogenesis fo some animals by drawing the analogy from one dimensional Ising model.

2 illus, 6 ref

000023   Baishya R K;Devi M;Barbara A K (Department of Physics, Gauhati University, Guwahati-781 014) : Software development for lidar data analysis. Indian J Radio Space Phys 2003, 32(2), 114-17.

A micro pulse lidar (MPL) system was developed and installed at the Department of Physics, Gauhati University, Guwahati, and is in operation from January 2001. The lidar system receives backscattered signal from aerosols and clouds up to a height of 15 km at a resolution of 15 and 30 m. Describes the software developed for profiling of aerosols and clouds and also processing technique of the basic data through various tools. The software also takes care of monitoring and recording the system parameters and background conditions. Shows some sample outputs of the programme.

^ssc7 illus, 2 ref

000022   Bailin D (Centre for Theoritical Physics, University of Sussex, Brighton BN1 9QJ, UK) : Standard model on D-branes. Pramana J Phys 2003, 60(2), 199-208.

Outlines previous work on getting the (supersymmetric) standard model from string theory, and then describe two ecent attempts using D-branes. The first uses D3- and D7-branes and gives a supersymmetric standard model with extra vector-like matter and an intermediate unification scale. The second uses intersecting D4-branes and yields a non-supersymmetric spectrum with TeV-scale unification.

2 tables, 28 ref

000021   Allanach B C (TH Division, , CERN) : Measuring supersymmetry at the large hadron collider. Pramana J Phys 2003, 60(2), 239-47.

The large hadron collider (LHC) should have the ability to detect supersymmetric particles if low-energy supersymmetry solves the hierarchy problem. Studies of the LHC detection reach, and the ability to measure properties of supersymmetric particles are currently underway. Highlights some of these, such as the reach in minimal supergravity space and correlation with a fine tuning parameter, precision measurements of edge variables, anomaly- or gauge-mediated supersymmetry breaking. Supersymmetry with baryon-number violation seems at first glance more difficult to detect, but proves to be possible by using leptons from cascade decays.

7 illus, 18 ref

000020   Alex S;Chandra H;Rastogi R G (NO, Indian Institute of Geomagnetism, Colaba, Mumbai-400 005) : Association between equatorial and tropical spread-F. Indian J Radio Space Phys 2003, 32(2), 83-92.

Comparitive study of spread-F is made from the quarter-hourly ionograms at Huancayo, near the magnetic equator and Bogota, close to the anomaly crest region in the same longitude sector. The occurence of equatorial spread-F is seen only during nights, preceded by very rapid rise of the F-layer close to the magnetic equator. Based on quarter-hourly ionospheric data at a closely spaced chain of 8 stations in the American sector that operated during IGY, the occurence of spread-F at low latitudes is shown to be associated with the post-sunset intensification of the ionization anomaly. The ratio of f₀F2 at Bogota (anomaly crest) to that at Huancayo (dip equator) shows sudden intensification on spread-F days around 1900 hrs LT, peaking between 2000 and 2100 hrs LT and can be used as a precursor to predict spread-F near the magnetic equator. The onset of spread-F at Bogota, however, requires additional condition of strong spread-F at Huancayo covering a wide range of altitudes and stronger uplift of the F-layer. There are indications that the vertical uplift velocity of F-layer between 1800 and 1900 hrs LT could be used to predict the onset of equatorial spread-F even at crest.

9 illus, 34 ref

000019   Acharya B S (Regional Research Laboratory, , Bhubaneswar-751 013, Orissa) : Band structure studies in solid using X-ray spectroscopy. Indian J Phys-Pt A 2003, 77(2), 103-7.

Usefulness of X-ray spectroscopic investigation on some metals, alloys, semiconducting thin films and unsulating materials is highlighted. Study on these samples have shown the type of bonding present in alloy thin films, charge associated with different atoms, density of states present on the top of valence band and near the Fermi level. Further, the role of Coster-Kronig process of vacancy production, many electron effects and exchange interaction between d and p states are also discussed.

2 illus, 38 ref

000018   Abe K (NO, High Energy Accelerator Research Organization, 1-1, Oho, Tsukuba, Ibaraki, 305-0801, Japan) : Selected topics from Belle. Pramana J Phys 2003, 60(2), 337-44.

The Belle experiment continues to explore the origin of CP violation and test all aspects of standard model in B meson decays. Recent results on CP violating parameter sin2φ₁ and other measurements are presented.

7 illus, 4 ref

000162   Whitaker A (Queen's University, , Belfast, Belfast BT7 1NN, Northern Ireland, UK) : Information flow in quantum teleportation. Pramana J Phys 2002, 59(2), 255-61.

The flow of information is discussed in the context of quantum teleportation. situations are described which used a sequence of systems of particles in which, though there is no claim of faster-than-light signaling, it is possible to suggest that information about mesurement procedures in one wing of the apparatus does reach the other end in a non-local manner. The definition of the term `parameter dependence' is discussed.

9 ref

000161   Wang D-S (Institute of Physics, Chinese Academy of Sciences, Beijing-100 080, China) : Linear and nonlinear optical properties of borate crystals as calculated from the first principles. Bull Mater Sci 2003, 26(1), 159-63.

With the development fo the state-of-the-art band calculated scheme and massively parallel processing in the high performance computing, it is now possible to calculate all important physical properties, including the nonlinear susceptibility; the multiphoton absorption rate; the birefringence; and the energy gap, from the first principles for complex practical nonlinear optical crystals, such as the borate crystal series, with an accuracy acceptable for materials development/design, and answer the questions often raised by the material scientists.

4 tables, 23 ref

000160   Vijay Kumar (NO, Institute for Materials Research, Thoku University, 2-1-1 Katahira, Aoba-ku, Sendai-980-8577, Japan) : Novel caged clusters of silicon: fullerenes, Frank-Kasper polyhedron and cubic. Bull Mater Sci 2003, 26(1), 109-14.

Recent findings of metal (M) encapsulated caged clusters of Si and Ge obtained from computer experiments based on an ab initio pseudopotential method have been reviewed. It is shown that one M atom changes drastically the properties of Si and Ge clusters and that depending upon the size of the M atom, cages of 14, 15, and 16 Si as well as Ge atoms are formed. In particular M@Si16 silicon fullerene has been obtained for M=Zr and Hf, while a Frank-Kasper polyhedron has been obtained for M@X16, X=Si and Ge. These clusters show high stability and large highest occupied-lowest unoccupied molecular orbital (HOMO-LUMO) gaps which are likely to make these species strongly abundant. A regular icosahedral M@X12 cluster has also been obtained for X=Ge and Sn by doping a divalent M atom. Interactions between clusters are rather weak. This is attractive for developing self-assembled cluster materials.

5 illus, 2 tables, 14 ref

000159   Verma A K;Ravindran P;Rao R S;Godwal B K; Jeanloz R (High Pressure Div, Bhabha Atomic Research Centre, Mumbai-400 085) : On the stability of rhenium up to 1 TPa pressure against transition to the bcc structure. Bull Mater Sci 2003, 26(1), 183-7.

Electronic structure total energy calculations were carried out on rhenium in the hexagonal close packed (hcp) and body centred cubic (bcc) phases, by the full potential linear muffin-tin orbital method, in order to verify the stability of the ambient pressure hcp phase against transition to the bcc structure at high pressures. As per the results, no hcp to bcc structural transition can occur up to 1 TPa pressures. Moreover, Bain path calculations show that face centred cubic and body centred tetragonal structures are also not energetically preferred over hcp in this pressure range. The axial ratio (c/a) of Re changes by less than 0.33% in the pressure range studied.

5 illus, 20 ref

000158   Valentine A (Theoretical Physics Group, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ, England) : Subquantum information of computation. Pramana J Phys 2002, 59(2), 269-877.

It is argued that immense physical resources - for nonlocal communication, espionage, and exponentially-fast computatin-are hidden from us by quantum noise, and that this noise is not fundamental but merely a property of an equilibrium state in which the universe happens to the at the present time. It is suggested that `non-quantum' or nonequilibrium matter might exist today in the form of relic particles from the early universe. Describe how such matter could be detected and put to practical use. Nonequilibrium matter could be used to sent instantaneous signals, to violate the uncertainty principle, to distinguish non-orthogonal quantum states without disturbing them, to eavesdrop on quantum key distribution, and to outpace quantum computation (solving NP-complete problems in polynomial time.

36 ref

000156   Unnikrishnan C S (Gravitation Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005) : Proof of absence of spooky action at a distance in quantum correlations. Pramana J Phys 2002, 59(2), 295-301.

Prove that there is no spooky action at a distance and nonlocal state-reduction during measurements on quantum entangled systems. The prediction of quantum theory as well as experimental results are in conflict with the concept of nonlocal state-reduction, as consulsively shown here under very general assumptions. This has far-reaching implications in the interpretation of quantum mechanics in general, and demands a radical change in its present interpretation of measurements on entangled multiparticly systems. Motivated by these results we re-examine Bell's theorem for correlations of entangled systems and find that the correlation function used by bell fails to incorporate phase correlations at source. It is the use of such an unphysical correlation function, and not failure of locality, that leads to the Bell's inequalities.

1 illus, 11 ref

000155   Stefanov A;Zbinden H;Gisin N;Suarez A (Group of Applied Physics, University of Geneva, 1211 Geneva 4, Switzerland) : Quantum correlation with moving beamsplitters in relativistic configuration. Pramana J Phys 2002, 59(2), 181-8.

Present a recent experiment using space-like beamsplitters in motion revealing a new features of quantum nonlocality: The correlations caused by two-particle quantum entanglement are not only independent of distance (as we already know from the conventional Bell-type experiments) but also independent of the time-ordering between the two single-photon measurements. Hence, it seems impossible to cast them in any real time ordering and maintain a causal explanation in which an earlier event influences a later one by arbitrarily fast communication.

4 illus, 26 ref