- #1
karlthecar1
- 1
- 0
Hello,
I am constructing a 2d atomistic mass spring Hamiltonian with nearest neighbor bonds (harmonic potential) in an attempt of calculating the phonon dispersion. I solve the eigenvalue system and calculated the eigenvalues or phonon energy levels (y-values of dispersion). I am fine up to that point. So my question is how to correctly determine the wavevector (k) from the eigenvalue solution to plot omega vs. k/a. If I look at the mode shape (eigenvectors) for each eigenvalue can I determine the wavevector? If that is the case do I select a single atom within the lattice and look at the neighbors or do I have to do and average over all atoms? My next question is going to be how do you discern transverse from longitudinal modes. Any help would be great.
Thanks
I am constructing a 2d atomistic mass spring Hamiltonian with nearest neighbor bonds (harmonic potential) in an attempt of calculating the phonon dispersion. I solve the eigenvalue system and calculated the eigenvalues or phonon energy levels (y-values of dispersion). I am fine up to that point. So my question is how to correctly determine the wavevector (k) from the eigenvalue solution to plot omega vs. k/a. If I look at the mode shape (eigenvectors) for each eigenvalue can I determine the wavevector? If that is the case do I select a single atom within the lattice and look at the neighbors or do I have to do and average over all atoms? My next question is going to be how do you discern transverse from longitudinal modes. Any help would be great.
Thanks