ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
It is observed that, for molecular crystals, during phase transitions the Raman intensities of the vibrational modes obey the power law |T−Tc|β. The exponent β contains much critical information and is mode dependent. The scaling properties of the doped materials are imbedded in β which is found to be very sensitive to very small degrees of doping. One of the eminent phenomena is the so-called crossover point where β of the totally symmetric ν1 mode equals the nonsymmetric ν4 mode of the nitrate ion. The scaling is expressed through the scaled coordinate d/M1/2 where d is the averaged interdoped-cationic distance and M is the mass of the cation. β of the ν1 mode behaves as (d/M1/2)γ with exponent γ rather independent of the transitions and the kinds of doping. Resonant modes due to doped cations are employed to explain the origin of the scaling. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.476211
