Polarized electronic absorption spectra of 3d3-configurated tetravalent manganese in octahedral fields of Mn(SeO3)2

✍ Scribed by M. Wildner; K. Langer

• Publisher: Springer-Verlag
• Year: 1994
• Tongue: English
• Weight: 513 KB
• Volume: 21
• Category: Article
• ISSN: 0342-1791
• DOI: 10.1007/bf00202093

✦ Synopsis

Polarized optical absorption spectra of Mn (IV) in octahedral crystal fields of Mn(SeO3)2 have been studied by means of microscope-spectrometry in the range 40 000 -4000 cm-1 and at temperatures between 113 K and 293 K. Intense charge-transfer absorptions (linear absorption coefficient c~ >> 30000 cm-1) completely mask the d-d transitions in the UV and VIS region above ~23000cm -1. The optical electronegativity Xovt of Mn(IV) in Mn(SeO3)2 is estimated to be < 2.7. In accordance with the d 3 configuration of tetravalent manganese three d-d bands observed at ambient temperatures at 13250, 14137 (e~50 cm -1) and ~ 18500 cm -1 (c~ 500-800 cm -1) are assigned to the spin forbidden 4Azg--~ 2Eg and 4A 2.-->2T1o transitions as well as to the first spin allowed ~A2g ---> ~ T2g transition, respectively. These assignments allow the calculation of the following ligand field parameters:

Dq~ 1850 cm 1, B55=869 cm-1 (fl55=0.82), and C=2346 cm -1 (293 K).