Detection and assignment of weak absorption bands by magnetic circular dichroism: Spin-forbidden transitions of CoCl42−
✍ Scribed by J.A. Lomenzo; B.D. Bird; G.A. Osborne; P.J. Stephens
- Publisher
- Elsevier Science
- Year
- 1971
- Tongue
- English
- Weight
- 345 KB
- Volume
- 9
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The magnetic circulnr dichroism (MCD) of CoC1~-~~CsgZnC15 at S°K shows ten weak bands between 8000 A and 3000 A due to spin-forbidden transiUoas. The signs and magnitudes of the MCD intensities yield n clear nssignmcnt of nine bands. We report here preliminary measurements of the magnetic circular dichroism (MCD) of CoCli-in Cs3ZnCl5 which provide assignment of ten spin-forbidden d -) d transitions and demonstrate the value of MCD in studying weak absorption bands. The axial absorption spectrum of Cs3Zn(Co)Cls measured with a Cary 14 and at 9'K is shown in fig.
la. The crystal of the 4A2 -a sed was about 0.1 mole % 'and 1 mm thick, these together being optimal for the study 4Tf band at ~15 000 cm-l. In addition, very weak absorption is observed at 13 400, 16 300, 1'7 300, 18 700 and 22 300 cm -1. The MCD of the same crystal measured*** with a Gary 61 spectropolal-imeter and a Varian Associates superconducting magnet at 9'K and 48 kG is illustrated in figs. lb and 2. MCD is seen r?ot only where absorption was encountered but also in many other, apparently transparent, regions. Considerable structure is observed in all bands, in several cases not fully re-