Recently multi-atom resonances in photoemission of transition metal oxides
were observed by Kay et al. [A. Kay, E. Arenholz, S. Mun, F.J. Garcia de Ab
ajo, C.S. Fadley, R. Denecke, Z. Hussain, M.A. Van Hove, Science 281 (1998)
679]. We present the results of a systematic study of multi-atom resonant
photoemission in transition metal chlorides. We measured the intensity of t
he chlorine 2p photoelectron line excited around the metal 2p photoabsorpti
on edge of the transition metal compounds MnCl2, CrCl2, and VCl2 as well as
of the ionic solid KCl. Our experimental results show that the intensity o
f Cl 2p photoelectron lines enhance by about 29% for MnCl2, 21% for CrCl2,
17% for VCl2 and 11% in the case of KCl at the metal 2p photoabsorption edg
e. We ascribe the systematic decrease of the magnitude of this effect, goin
g from MnCl2 to KCI, to the extension of the excited metal 3d wavefunction
and, as a consequence, decrease of the overlap between the 3d and 2p atomic
orbitals. (C) 2000 Published by Elsevier Science Ltd.