Dear All,

I have a question that is not directly related to Athena or Artemis but it is more related with EXAFS theory. I work on lithium metal oxides and sometimes measure their XAS data. XAS data show typical trend, i.e; first prominent peak related with metal-oxygen co-ordination shell and second prominent peak is associated with metal-metal co-ordination shell in my materials. I have noticed that in similar crystal structures Li2MO3-type (where M is transition metal), if metal belongs to 3d transition metal groups I get a single prominent metal-metal peak but for 5d transition metals, the metal-metal peak splits and its intensity also drops. I could not figure out the reason for the splitting of metal-metal peak in case of 5d metals. I have attached a PDF file in which calculated EXAFS spectra for Li2RuO3 (4d transition metal) and Li2PtO3 (5d transition metal) are shown and metal-metal (Pt-Pt) peak in Li2PtO3 shows clear splitting whereas metal-metal peak for Li2RuO3 does not split even though their “ATOMS” input files are very similar.

I would appreciate if anybody could briefly explain the reason for metal-metal peak splitting in 5d metals or point me towards any literature. Attachment can be downloaded from the below link as well.

https://www.dropbox.com/s/1m3kf764junuukk/Metal-Metal%20Peak%20Splitting%20in%205d.pdf?dl=0

Thanks,

Shoaib Muhammad

Department of Energy Science

Sungkyunkwan University (South Korea)