Bhattacherjee, S B

Gupta, K Das

English

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67SOFT X-RAY L-SPECTRA OF Fc, Co. Ni, Cu ANDTHEIR o llD E S *B y  K .  d a s  GU PTA and S. h .  BHATTACHERJEE{R e c e iv e d  fo r  p u b l i c a t i o n j ^ o v e m b e r  9, ig.fi)■ ABSTRACT. L2, 3 band spectra of Fe—Co w the region ij-r S  A. U. with bent mien and gyp spe^rograph. I.3 bands of Fe—Ni have more or In these elements a weak extended structure band ha.a been observed. The main Lo band havi wfth its extended strnctnre on the shorter wavelength side has been considered to be the valence bands of these elements.their oxides have been investigated in crystal in a Siegbnhn*s vacuum grating s the same energy width of 13—16 eV. the short wavelength side of the main g a width of 5eV approximatelv, alongI N T R O D U C T I O NThe valence bauds of the elements iron, cobalt, nickel and copper consist overlapped 3d ; 44-, p bands. Ea. 3 valence band spectra of these elements.reflect the energy spectra of 3d, 4.1 electrons. The wavelength range of Es.s radiations lie between 13 -18  A. and is too short compared* to their M spectral region. Thus there will be some broadening of the edges due to the radiation damping in the case of the Ls.s valence band spectra ; while in the case of M spectra, due presumably to the Auger broadening of the X-ray levels, the valence band will have some broadening effect. Moreover, Ms and Ms bands might overlap quite considerably creating complications in the point of analysis, while in the La, s region of these elements, the La and La bands are distinctly separated from each other.The L bands of metals Fe-Ge were investigated by Gwinner (1938) using a bent crystal spectrometer.The present investigation was undertaken to obtain, La. s bands of Fe-Cu in pure elements and in their oxides. In the case of copper oxide, special attention was given to investigate the difference in the band pattern of cuprous oxide from that of cupric oxide. Special care was taken to keep the metal surface of the target of the X-ray tube free from oxidation when studying the pure elements.E X P E R I M E N T A L  R E S U L T SLa. s bands of Fe, Co, Ni and their oxides have been investigated with a bent mica crystol in a Siegbahn’s vacuum grating spectrograph. For the investigatiou of La, s bands of copper and its oxides, a bent gypsum crystal was used. Fine platinum wire coated with suitable oxides was Used as a * Conmittttfcatied'by Prof. S. NV Bose.m K. Dat .Gttpki card-rated from the ha  baud. The peak position o f  the ha  band is at X5»930 X.U. There is a sign of a distinct short wavelength' structure at X5*90^  X.U- This structure appears prominently in Co-Cu alloys.N ic ke l.— The width of the La-ban4 of nickel is 15.8 eV. The peak at 14*530 X.U., lies towards th^Jow "gnergy side of the band. The tuctension on the shorter wavelength side of the main peak is quite prominent, the case of nickel oudg^Jthe total iaaad-wid^ of band-fe nearly of the shmewidth as that in pm«'Nickel."‘“T'EFpromine»it Structure X4*423 X.U. in the case of nickel oxide is clearly noticjeable uhltfce the oxides of iron and cobalt.Copper.— ha  or ha band of eteCtrplytic cppper is a broad band having a width of about 19 .0  eV. with_three"di8tinct structures„iiuHl€ L» band at 13,325, 13,267 and x3,265'‘’X.tJ. In CuO  ^ the band pattern changes considerably, as shown in the nticrophotoipef^ records. ‘ In CuaO, there is a prominent long wavelength Jailing not tb be found in CuQ or Cu.C O N C I / U S i b N  ^IThe investigation of ha  bands of Fe-Cu and their oxides clearly points out the following facts:(1) The valence bands, viz : - ^  ; 4^ , p bands, of alTtheSe elements con­sist of a broad band with structure,(2) The widths of Ua band of these elements are fairly of the same order (Table I). t! • .T able IWidths of 1,3 of band in eVFe Fe»04 Co CoO Nii Nio Cu CtijO , Cao13.3 13.0 *3-7> . ,15.8 i7 .o 19.0 " 24.0 19.0' - (3)" The chahge'in the baud pattern of Ls band in The ca^ of ^  oxides pomWout a change in the distribution of electron density ifi the Valedi^'l^d. The Ctoss-tranSition effect wilt also be responsible'for . the difference iff hand pattern. Electrons behaving as oxyged 2p can easily fill ttb the XV vacancy cff the' metal ion, in which case, the seleclhm princil>1e*1s t ib i disobeyed.(4! The most „ ptomineht structure of !«» band of these elements on the' low energy side, usually.referred to as h a , p<^ibly represents 3d electrons, Which shifts towards the' shorter wavelength side in the case of oxides. In the case of Mg, A 1, Si oxides, the shift of the valence .baud of the inetal . id towards the. longer wavetin g^rti “ . ’ ' !  ^ ‘ .A C K N O W I r E D G M E N TT h e authors are thankful to Prof . S  . N  . Bose , Khaira Professor of P h ysics, for his keen interest and helpi|al discussion during the progress of the work.K haira Z/Aboraxory op Physics.University Coi,i:,egb ob Science, CA£,cuti,Soft X-’Tsy L^Spectra of Fe» Co, N/, Cu and thdr Oxides 559r e f e I e n c e sDas Gupta. K ., 1950, D Sc.Dissertation(C^/* Gwinuet, 1938, Z . f .  P h y s . ,  108, 523,. Skinner, 1940, P h i l .  T ra ns.,  2

Soft X-ray L-spectra of Fe, Co, Ni, Cu and their oxides

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Soft X-ray L-spectra of Fe, Co, Ni, Cu and their oxides

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