| Popis: |
A re-examination of the luminescence and absorption spectra of the title compounds shows that the nitrate salt contains Cr(urea)6+3 ions on at least five distinct lattice sites. These ions are excited both directly and by intermolecular energy transfer. In the bromide salt at least four of the 4A2→2E, 2T1 origins may be identified although there is appreciable interaction between the electronic and vibronic states involved. Although the 4T2 electron origins occur a few hundred wave-numbers above the 2E origins, transitions to these levels are not definitely observed. There is no evidence for a Jahn–Teller effect in the 2E, 2T1 states nor for appreciable magnetic coupling between the Cr(urea)3+6 ions. |
