This python (python.org) script (bondlength_energies.py) can be used for parsing the geometry.xyz ouput geometries (typically optim.xyz or scan_optim.xyz) from a potential energy surface search in Terachem (petachem.com). This version, by title only, is used to extract the enegies for bond-length searches but is equally suited for variation in other geometry features, e.g. bond angles. It extracts the energies (in Hartrees) for each frame from the xyz file and plots them using matplotlib (matplotlib.org), for quick viewing.