Generic Linear Response Kernel

As an alternative one can use the generic linear response kernel for PHONONPHONON. This options supports the Hockney poisson solver, but does not handle symmetry.

&CPMD
  LINEAR RESPONSE
  RESTART COORDINATES WAVEFUNCTION
  CONVERGENCE ORBITALS
     1.0D-7
&END

&RESP
  PHONON
&END

******************************************************************
 Raw second derivative matrix: No trans/rot elimination
  Harmonic frequencies in cm^-1:
      -214.6      -100.8       -61.5       -36.8
        35.5       216.4      1581.4      3713.1
      3821.8
 Translations eliminated from second derivative matrix
  Harmonic frequencies in cm^-1:
       -93.9       -39.0         0.0         0.0
         0.0        35.5      1581.4      3713.1
      3821.8
 Projection (by PURGED routine):
  Harmonic frequencies in cm^-1:
         0.0         0.0         0.0         0.0
         0.0         0.0      1621.8      3722.2
      3815.3