  We present a Path Integral Monte Carlo calculation of the first three moments
of the displacement-displacement correlation functions of solid neon at
different temperatures for longitudinal and transverse phonon modes. The
Lennard-Jones potential is considered. The relevance of the quantum effects on
the frequency position of the peak and principally on the line-width of the
spectral shape is clearly pointed out. The spectrum is reconstructed via a
continued fraction expansion; the approximations introduced using the effective
potential quantum molecular dynamics are discussed.
