Inspired by the calorimetric and dielectric properties studies on a novel organic anitferroelectric compound, dtBBP - CLA , this proposal seeks to compare and extend the methodology to further corroborate the model of hydrogen dynamics across the hydrogen bond that seems to explain the ferroelectric phase transition at both native and deuterated systems. Using selective deuteration of the hydrogen bond site-selectivity of NCS will be achieved in dtBBP - CLA.Deuteron momentum distribution and subsequently the shape of the Born-Oppenheimer potential felt by deuterons in the hydrogen bond will be reconstructed to assess the degree of deuteron wave function coherence below and above the ferroelectric phase transition.