transition energies of neutral and singly ionized...

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Indian J. Phys. 84 (3) 223-230 (2010) Transition energies of neutral and singly ionized lanthanum Betül Karaçoban and Leyla Özdemir* Department of Physics, Sakarya University, 54187, Sakarya, Turkey E-mail : [email protected] Received 4 August 2009, accepted 25 January 2010 Abstract : We have calculated the transition energies (ionization potential, excitation energies, electron affinity) of neutral lanthanum (La I) and singly ionized lanthanum (La II). The calculations are based upon the multiconfiguration Hartree-Fock (MCHF) method within the framework of Breit-Pauli relativistic corrections. These energies are important for determination of physical and chemical properties for La I and La II. Results obtained have been compared with other works. Keywords : Energy levels, MCHF method, relativistic corrections. PACS Nos. : 31.15.ag, 31.15.aj

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Page 1: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 223-230 (2010)

Transition energies of neutral and singly ionized lanthanum

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Abstract : We have calculated the transition energies (ionization potential, excitation energies, electronaffinity) of neutral lanthanum (La I) and singly ionized lanthanum (La II). The calculations are based upon themulticonfiguration Hartree-Fock (MCHF) method within the framework of Breit-Pauli relativistic corrections.These energies are important for determination of physical and chemical properties for La I and La II. Resultsobtained have been compared with other works.

Keywords : Energy levels, MCHF method, relativistic corrections.

PACS Nos. : 31.15.ag, 31.15.aj

Page 2: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 231-243 (2010)

Double charge transfer cross sections in collision of protonswith helium atom

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Abstract : Theoretical total cross sections for the double charge transfer in proton-helium collisions areanalysed using the four-body boundary corrected continuum intermediate state approximation in the energyrange of 30 to 500 keV. We have also obtained differential double capture cross sections as a functions ofprojectile scattering angle. The intermediate continuum state of each of the active electron has been taken intoaccount in this formalism. Our calculated results are compared with the previous experimental and theoreticalvalues. The agreement is very encouraging.

Keyword : Ion-atom collision, double charge transfer, cross sections.

PACS No. : 34.70.+e

Page 3: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 245-256 (2010)

All-electron relativistic calculation on Au5X (X = Sc, Ti, V,Cr, Mn, Fe, Co, Ni, Cu and Zn) clusters

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Abstract : All-electron scalar relativistic calculations on Au5X (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn)clusters have been performed by using density functional theory with the generalized gradient approximation.Our calculation results indicate that all the lowest energy geometries of Au5X clusters have planar structures;the doped X atoms prefer to occupy the fourfold coordination site. Except Au5Fe, Au5Co and Au5Zn, for otherclusters including pure Au6 cluster, the HOMO are delocalized obviously with a contribution from all atoms in thecluster. On the contrary, the electron localization in Au5Zn is very strong resulting in the least stability of thiscluster. Au5Cu cluster with six delocalized electrons being defined as magic number for two-dimensional systemhas the largest VIP and deepest HOMO energy level. With the substitution Au for X atoms, the metallicity of allAu5X clusters is reinforced.

Keywords : Au5X (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) clusters, geometrical structures, electronicproperties.

PACS Nos. : 73.22.-f, 36.40.Cg, 36.40.Ei

Page 4: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 257-264 (2010)

Ground state phase diagram of the 1D XXZ model in atransverse magnetic field

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Abstract : The Ground state phase diagram of the 1D spin-1�2 XXZ model in a transverse magnetic field isstudied by the numerical Lanczos method. Also by computing the energy gap and different spin-spin structurefactors, quantum phase transitions in whole range of the anisotropy parameter are determined.

Keywords : Ground state, spin chain, Heisenberg model, quantum phase transitions, phase transitions,transverse magnetic field.

PACS Nos. : 75.10.Jm, 75.10.Pq

Page 5: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 265-277 (2010)

(InSb/GaAs)-Au hybrid macro-structure prepared by flashevaporation

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Abstract : n-Type indium antimonide-Au hybrid macro-structure was successfully fabricated on p-GaAssubstrate by a simple and economic flash evaporation technique. The elemental composition of the preparedInSb film was confirmed by energy dispersive X-ray spectroscopy microanalysis (EDX). The surface topographyand crystal structure of the InSb film was characterized by scanning electron microscopy (SEM) and X-raydiffraction (XRD), respectively. The magnetoresistance of the prepared hybrid macro-structure was measuredand discussed in terms of the model of current redistribution.

Keywords : InSb-Hybrid macro-structure, flash evaporation, magnetoresistance

PACS Nos. : 73.40.Qv, 73.43.Qt, 79.70.Tq

Page 6: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 279-289 (2010)

Coexistence of Jahn-Teller effect and superconductivity inhigh-Tc superconductors

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Abstract : Using a simple model, the coexistence of superconductivity (SC) and the Jahn-Teller (JT) effectare studied for high-Tc cuprate systems. The interplay of SC and JT gaps is studied and found that in thecoexistence phase the SC gap as well as the JT gap are suppressed. For calculations, the single particle Green’sfunction technique of Zubarev is used. The density of states (DOS) and dispersion curves are also studied in thecoexistence phase.

Keywords : High-Tc superconductors, Jahn-Teller effect, cuprate superconductors.

PACS Nos. : 74.90.+n, 71.70.Ej, 74.72.-h

Page 7: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 291-299 (2010)

Voice onset time as a perceptual cue in voicing contrast inTulu language

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Abstract : Voice onset time (VOT) is a perceptual cue in voicing contrast of stops in the word initial position.The current study aims to acoustically and perceptually characterize VOT in one of the major South Indianlanguages - Tulu. Stimuli consisted of 2 pairs of meaningful words with velar [/p/-/b/] and bilabial stops and [/k/-g/]in the initial position. These words were uttered by 8 normal native speakers of Tulu and recorded using Praatsoftware. Both spectrogram and waveform views were used to identify the VOT. For perceptual experiment, 4adult native speakers of Tulu were asked to identify the stimulus from where voicing was truncated in steps of5 to 7 ms till lead VOT was 0 and silence was added after the burst in 5 msec steps till the lag VOT was 50 msec.The reaction time and the accuracy in identification were measured. Results of acoustic measurement showedno significant mean difference between lead VOTs of two voiced consonants. However, there was a significantdifference between means of lag VOTs of voiceless consonants. Results of Perceptual measurement showedthat as lead VOT reduces, probability of indentification of /g/ responses reduces; whereas changing VOT hadlittle effect on reaction time and identification of /b/ responses. These results probably indicate that VOT is notnecessary to perceive voiceles constants in Tulu but is necessary in the perception of voiced consonants. ThusVOT is a constant specific cue in Tulu.

Keywords : Acoustic analysis, lead VOT, lag VOT, reaction time, identification score.

PACS Nos. : 43.71.Es, 43.71.Gv, 43.71.Sy

Page 8: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 301-307 (2010)

A voltmeter with browser-based control : an inexpensiveinstrument

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Abstract : This paper presents a home-made voltmeter which has browser-based controls. The voltmeteris basically an analog-to-digital converter implemented with a microprocessor and some supporting circuitry. Thebrowser-based control system enables one to access the voltmeter through the Internet from anywhere in theworld. The control of the instrument is solely through any standard web browser running on any platform; noadditional client software is required.

Keywords : A/D converter, in-house built, browser-based, OS-independent, CGI programme, free software.

PACS Nos. : 07.05.Bx, 07.05.Hd, 07.05.Wr

Page 9: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 309-317 (2010)

Influence of temperature on neuronal excitability in

cochlear nucleus

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Abstract : The influence of temperature on neuronal excitability is studied by numerical simulations on thespiking threshold characteristics of bushy cells in cochlear nucleus periodically stimulated by synaptic currents.The results reveal that there is a cut-off frequency for the spiking of bushy cell in a specific temperatureenvironment, corresponding to the existence of a critical temperature for the neuron to respond with real spikesto the synaptic stimulus of a given frequency, due to the finiteness of spike width. An optimal temperature rangefor neuronal spiking is also found for a specific stimulus frequency, and the temperature range span decreaseswith increasing stimulus frequency. These findings imply that there is a physiological temperature range whichis beneficial for the information processing in auditory system.

Keywords : Neuronal excitability, temperature influence, stimulus frequency, spiking threshold.

PACS Nos. : 87.19.Dd, 87.10.+e, 87.17. Aa, 87.19.La

Page 10: Transition energies of neutral and singly ionized …mailweb.iacs.res.in/ijp/ijp_march_2010_abstract.pdfTransition energies of neutral and singly ionized lanthanum ... Our calculated

Indian J. Phys. 84 (3) 319-324 (2010)

Low frequency electromagnetic waves in a multi-ionplasma

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Abstract : The dispersion characteristics of low-frequency electromagnetic waves are studied in a plasmacontaining hydrogen ions and positively and negatively charged oxygen ions and electrons. This composition ofthe plasma approximates very well the coma of comet Halley where many heavy ions have been observed inappreciable numbers. The excitation of these waves results from the relative motion between the protons andthe heavy ions, which are considered unmagnetised and, therefore, may act like a beam. We find that the wavegrowth increases with increasing heavy ion densities, beam velocities and propagation angles.

Keywords : Electromagnetic waves, multi-ion plasmas, negative ions, stability, low frequency electromagneticwaves in a multi-ion plasma.

PACS Nos. : 96.50.Gn, 96.50.Ry