# Reading complex potential into CP2K

Is it possible to read a complex potential into CP2K? I have generated a potential using FDTD at a given frequency, which results in a complex result. The potential is to be read in to a real time propagation method as a static background potential.

If I'm interpreting the manual correctly, it is not possible to define a complex external potential in CP2K. It specifies that the VALUES keyword to define the corresponding PARAMETERS of your potential has to be real. I don't know anything about the internal code of CP2K, so I don't know if this would be a simple modification of the code to accept complex inputs in this function or a more extensive overall of the code to handle complex values throughout.