American Chemical Society
ic001364v_si_001.pdf (3.56 MB)

Interference Dips in the Single-Crystal Absorption Spectrum of the Tri-μ-fluoro−Bis(trifluorochromate(III)) Complex

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journal contribution
posted on 2001-10-09, 00:00 authored by Ralph Schenker, Myriam Triest, Christian Reber, Hans U. Güdel
The lowest energy spin-allowed crystal field band of (Et4N)3Cr2F9 shows a distinct interference dip at 15000 cm-1 with an approximate width of 200 cm-1. This spectroscopic feature is due to spin−orbit coupling between the 2E and 4T2 excited states and is analyzed with a set of two coupled potential energy surfaces. The minimum of the 4T2 potential surface is displaced along at least two normal coordinates. The modes involved cannot be directly determined from the unresolved absorption spectrum, but are obtained from Raman spectra and from the well-resolved spin-forbidden crystal field transition to the 2A1 state. The first mode with a frequency of 415 cm-1 has predominant Cr−F stretching character; the second mode has a frequency of 90 cm-1 and involves the entire Cr2F93- dimer.