Method to determine the three-dimensional atomic structure of molecules

An x-ray method for determining the three-dimensional molecular structure of molecules having an unknown structure arranged in a two-dimensional periodic array on a substrate molecular crystal having a known structure, wherein the dimensions of the molecules with the unknown structure are smaller than the corresponding dimensions of the substrate crystal unit cell, said method comprising the following steps:

• measuring the x-ray scattering intensity;
• calculating the complex scattering factors (CSFs) of said two dimensionally periodic layer of said molecules with unknown atomic structure and the total CSFs of the system composed of said molecules arranged in a two-dimensional periodic array on said substrate molecular crystal from said measured x-ray scattering and the known CSF of said substrate molecular crystal;
• determining, from said calculated CSF of said two-dimensional periodic array, the electron density of said molecules arranged in said two-dimensional periodic array;
• and
• determining, from said electron density, the unknown structure of said molecules arranged in said two-dimensional periodic array.