  We present a detailed model atmosphere analysis of high-dispersion and high
signal-to-noise ratio spectra of the heavily polluted DAZ white dwarf GALEX
J1931+0117. The spectra obtained with the VLT-Kueyen/UV-Visual Echelle
Spectrograph show several well-resolved Si II spectral lines enabling a study
of pressure effects on line profiles. We observed large Stark shifts in silicon
lines in agreement with theoretical predictions and laboratory measurements.
Taking into account Stark shifts in the calculation of synthetic spectra we
reduced the scatter in individual line radial velocity measurements from ~ 3 to
< 1 km/s. We present revised abundances of O, Mg, Si, Ca, and Fe based on a
critical review of line broadening parameters and oscillator strengths. The new
measurements are generally in agreement with our previous analysis with the
exception of magnesium with a revised abundance a factor of two lower than
previously estimated. The magnesium, silicon and iron abundances exceed solar
abundances, but the oxygen and calcium abundances are below solar. Also, we
compared the observed line profiles to synthetic spectra computed with variable
accretion rates and vertical abundance distributions assuming diffusive
steady-state. The inferred accretion rates vary from dM/dt = 2x10^6 for calcium
to 2x10^9 g/s for oxygen. We find that the accretion flow must be oxygen-rich
while being deficient in calcium relative to solar abundances. The lack of
radial velocity variations between two measurement epochs suggests that GALEX
J1931+0117 is probably not in a close binary and that the source of the
accreted material resides in a debris disc.
