Usually, we can use non-analytical term correction to get LO-TO spliting when we calculate phonon dispersion. I am confused that how to distinguish long range force and short range force constant in phonon dispersion. I would like to extract long range force constant and short range force constant respectively. I have two problems:
1、X. Gonze et al. have give equation in 1997. I know Phonopy use their theory for non-analytical term correction. Could I extract extract long range force constant and short range force constant respectively by Phonopy?
2、Can I seperate omega_long_range and omega_short_range in boundary mode(not Γ point) like picture below? If so, How to do that ?
Looking for help. Thank you!