We study a partially ionized hydrogen plasma by means of quantum molecular
dynamics, which is based on wave packets. We introduce a new model which
distinguishes between free and bound electrons. The free electrons are modelled
as Gaussian wave packets with fixed width. For the bound states the 1s-wave
function of the hydrogen atom is assumed. In our simulations we obtain
thermodynamic properties in the equilibrium such as the internal energy and the
degree of ionization. The degree of ionization is in good agreement with
theoretical predictions. The thermodynamic functions agree well with results
from quantum statistics for 10000K < T < 40000K.Comment: 13 pages, Latex with 5 postscript figures, to be published in Phys.
Lett.