Soft X-ray absorption spectroscopy for chemical state analysis of Mn

Abstract

Mn L(sub 2, 3) soft X-ray absorption spectra of various manganese compounds were measured in order to analyze their chemical states using a synchrotron radiation facility. The sensitivity of absorption spectroscopy was controlled by Total Electron Yield (TEY) method or X-ray Fluorescence Yield (XFY) method. The procedure for the preparation of manganese samples and the conditions of the measurements were outlined. The representative L(sub 2, 3) absorption spectra of various Mn chemical states measured by TEY method were shown in figures. It was found that the spectra measured simultaneously by XFY method were significantly different from the TEY spectra, and that XFY spectra were broader than TEY spectra. The very sharp peaks have been found to emerge in the spectra of at 641 eV of Mn(V) and 643 eV of Mn(VII), and the reproducibility of these peaks has been examined at least three times, however, the origin of the sharp peaks were not able to be clarified. An unknown sample called as manganese blue has been measured, and it was found that the spectrum of manganese blue was composed of two equivalent intensity L(sub 3) peaks, which were assigned to Mn(IV) and Mn(VI) components.

マンガン化合物の化学状態を解析するため、種々のマンガン化合物のMnのL(sub 2, 3)系列の軟X線吸収スペクトルをシンクロトロン放射装置を用いて測定した。吸収スペクトルの感度は全電子収量(TEY)法またはX線蛍光収量(XFY)法を用いて制御した。マンガン試料の調整手法と測定条件の概略を記述した。TEY法を用いて測定した各種Mnの化学状態から代表的なL(sub 2, 3)吸収スペクトルを図に示した。同時にXFY法により測定したスペクトルはTEY法によるスペクトルと著しく異なること、そして、XFYスペクトルはTEYスペクトルよりも広いことが分かった。非常に鋭いピークがMn(V)の641eVとMn(VII)の643eVのスペクトルに現れることが分かり、これらのピークの再現性を少なくとも3回試験したが、鋭いピークの原因は明らかにできなかった。マンガンブルーと呼ばれる未知試料を測定し、マンガンブルーのスペクトルが2つの等輝度のL(sub 3)ピークから成り、Mn(IV)とMn(VI)成分によるものであることが分かった。