A hybrid Car-Parrinello QM/MM molecular dynamics simulation has been carried out for the Watson Crick base pair of 9-ethyl-8-phenyladenine and 1-cyclohexyluracil in deuterochloroform solution at room temperature. The resulting trajectory is analyzed putting emphasis on the N-H center dot center dot center dot N hydrogen bond geometry. Using an empirical correlation between the N center dot center dot center dot N-distance and the fundamental NH-stretching frequency, the time-dependence of this energy gap along the trajectory is obtained. From the gap-correlation function we determine the infrared absorption spectrum using lineshape theory in combination with a multimode oscillator model. The obtained average transition frequency and the width of the spectrum are in reasonable agreement with recent experimental data. (C) 2008 Elsevier B.V. All rights reserved.