Potential Field Acting on the Hydrogens in LAT (LiNH₄C₄H₄O₆·H₂O)

Abstract

In order to examine whether or not the O(5)–H(7) bond in the tartrate molecule in LAT could be actually a ferroelectric dipole, the potential field acting on the hydrogen H(7) was calculated. The negative charges on the oxygens in the tartrate molecule and the positive charges on NH₄ and Li were considered. The charges on O and H in OH were varied as a parameter. A certain shielding factor was multiplied for the fields which originated from farther ions. It was assumed further that the O(5)–H(7) bond could rotate around C(2)–O(5) axis keeping the angle (Remark: Graphics omitted.) constant. The result shows that an asymmetrical double minimum potential appears with the rotation of the O(5)–H(7) bond with the angular difference of about 100°, if the shielding factor and the effective ionic charges on O and H in OH are properly chosen; for example with the shielding factor of 1/5 and the effective charge of 0.7 e.