Hydrogen Bonds Behaviour in Brominated Betaine Calcium Chloride Dihydrate

The results of a comparative Raman scattering study of pure and Br - doped betaine calcium chloride dihydrate (BCCD) in the 12-300 K temperature range are reported. It is shown that bromine weakens hydrogen bonding, preventing in this way the localization of protons at low temperatures. Consequently for a high enough content of bromine, the non modulated ferroelectric phase is missing.