displacement¶
-
sisl.physics.phonon.
displacement
(mode, hw, mass)[source]¶ Calculate the real-space displacements for a given mode (in units of the characteristic length)
The displacements per mode may be written as:
\[\mathbf{u}_{i\alpha} = \epsilon_{i\alpha}\sqrt{\frac{\hbar}{m_i \omega}}\]where \(i\) is the atomic index.
Parameters: - mode : array_like
vectors describing the phonon modes, 2nd dimension contains the modes. In case of degenerate modes the vectors may be rotated upon return.
- hw : array_like
frequencies of the modes, for any negative frequency the returned displacement will be 0.
- mass : array_like
masses for the atoms (has to have length
mode.shape[1] // 3
Returns: - numpy.ndarray
displacements per mode with final dimension
(mode.shape[0], 3)
, the displacements are in Ang