  We present a new model atom of Zn I-II based on the most up-to-date
photoionisation cross-sections, electron-impact excitation rates, and rate
coefficients for the Zn I + H I and Zn II + H- collisions. The latter were
calculated using the multi-channel quantum asymptotic treatment based on the
Born-Oppenheimer approach. Non-LTE analysis was performed for the first time
for lines of Zn I and Zn II in the ultraviolet (UV) spectra of two very
metal-poor reference stars, HD 84937 and HD 140283. We found consistent non-LTE
abundance from the resonance Zn I 2138 A line, the subordinate lines, and the
lines of Zn II. In both stars, non-LTE leads to 0.17 dex higher average
abundance from Zn I, while, for Zn II lines, non-LTE corrections are minor and
do not exceed 0.06 dex. Using lines of Zn I in the high-resolution spectra, we
determined the non-LTE abundances for a sample of 80 stars in the -2.5 < [Fe/H]
< 0.2 metallicity range. The [Zn/Fe] versus [Fe/H] diagram reveals a dip, with
[Zn/Fe] = 0.3 in the most metal-poor stars, a close-to-solar value for [Fe/H] =
-1.2, and increasing [Zn/Fe] up to 0.3 in the thick disk stars. The
close-to-solar metallicity stars have subsolar [Zn/H] = -0.1, on average.
Non-LTE abundances of zinc were derived for the first time for seven reference
F to B-type stars. We provide a grid of the non-LTE abundance corrections.
