Partially proton-ordered ice I (cubic) was grown from the vapor phase,
from 40 to nearly 150 K. It is believed to be metastable and oriented
by the asymmetry of the solid-vacuum interface during growth. This wa
s studied using a Kelvin (work function) probe for ice grown on a sing
le-crystal Pt(lll) substrate. The ice grows with a slight preference f
or the O-end aimed away from the surface, with about 0.2% net up dipol
e per water molecule at 40 K, or about -3 mV/monolayer of deposited ic
e film. This decreases with deposition temperature as exp(-T/27 K). Ne
ar 130, 140, and 150 K sharp features occur as the ice changes from am
orphous to crystalline, and dielectric properties became active. By 15
0 K the effect seems to be zero. These results are discussed in contex
t with other recent reports on ferroelectric ice. In addition to influ
encing several kinds of vacuum-based studies of ice, this slight ferro
electricity may allow natural ice vapor-grown in space to develop larg
e electric fields.