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X‐Ray Photoemission Studies of the Ternary Intermetallic Compounds Li 2 MGa and LiMGa 2 (M = Rh, Pd, Ir, Pt)
Author(s) -
DrewsNicolai Lydia,
Hohlneicher Georg,
Hoppe Uwe,
Jung Walter
Publication year - 2001
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200106)627:6<1157::aid-zaac1157>3.0.co;2-9
Subject(s) - chemistry , intermetallic , fermi level , auger , binding energy , electronic band structure , spectral line , crystallography , ternary operation , atomic physics , valence (chemistry) , excited state , electron , condensed matter physics , alloy , physics , organic chemistry , quantum mechanics , astronomy , computer science , programming language
X‐ray photoelectron and x‐ray excited Auger spectra were measured for the intermetallic compounds LiMGa 2 and Li 2 MGa (M = Rh, Pd, Ir, Pt). The valence band spectra exhibit characteristic differences in the location of the M d‐band between group 9 elements (Rh, Ir) and group 10 elements (Pd, Pt) on one side and between LiMGa 2 and Li 2 MGa on the other. The experimentally observed differences are in excellent agreement with results from band structure calculations. The combination of binding energy shifts with Auger kinetic energy shifts allowed a separation of initial and final state contributions. Core hole screening is very efficient in accordance with the metallic character of the investigated phases. The magnitude of the screening correlates with the theoretically predicted composition of the density of states at the Fermi level. Application of Wertheim's electrostatic model allowed to estimate the charge distribution for LiRhGa 2 and Li 2 RhGa. The sign of the charges agrees with expectations that result from the Extended Zintl Concept. The results show, how dangerous it is to draw conclusions on the chemistry of such systems from photoemission data alone.