Prediction of pressure-induced red shift of f->d(t2g) excitations in   Cs2NaYCl6:Ce(3+) and its connection with bond length shortening
  Quantum chemical calculations including embedding, scalar relativistic, and dynamic electron correlation effects on Cs2NaYCl6:(CeCl6)3- embedded clusters predict: (i) red shifts of the 4f->5d(t2g) transition with pressure and (ii) bond length shortening upon 4f->5d(t2g) excitation. Both effects are found to be connected which suggests that new high pressure spectroscopic experiments could reveal the sign of the bond length change. 
Fernando Ruiperez, Luis Seijo, and Zoila Barandiaran