The scattering densities of the orientationally disordered protons and deuterons in Ni(NX,)bY? (X = H or D, Y = Br. 1. NO, or PFd %e obtained from neutron single-crystal diffraction data al room temperature. While we observe a nearly crrcular density distribution for Y = PF4. a nuclear density distribution with four maxima on a square shows up for Y = 51.I and Nos. This is 3 pronounced deviation from the circular distribution that is expected from uniaxial rotational diffusion or reorientational jump models for the dynamics of the Orientational disordered ammonia groups. All observed density distributions m consistently explained as the consequence of rotation-tmslationn coupling in an Mharmonic crystal potential. The calculated potential parameten. i.e. anharmonicily and strength of the coupling, depend on the type of anion present in the crystal frame. The we& anisompy in the Y=NOI and PF, compounds is the consequence of a nearly eightfold non-cvstallographic symmehy of the atom establishing the hindrance potential.
P Schiebel et ai
Potential reftnementWe determine the potential parameters A, B , C and the distance dp between the protons and the CM of the proton triangle by a least-squares analysis. by minimizing the residual
= ~[ P B a l a m u n n ( x i ~ J'i) -&'ohs(&.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.