Stacking modification in DNA-base molecule structures: X-ray diffraction on 5-Chlorouracil on Ag(1 1 1)

The geometric structure of the DNA-base derivative 5-Chlorouracil deposited on Ag(1 1 1) was analyzed using surface X-ray diffraction. Although the ad-layer structure bears many similarities with its bulk analog (e.g., lattice metric, hydrogen bonded molecules within each molecular layer and van der Waals interconnected layers), we find that subtle modifications of the interlayer molecular arrangement prevents the growth of films thicker than three layers.