TY - JOUR
T1 - Breakdown of the Gaussian approximation in semi-quantum liquids
AU - Celli, M.
AU - Colognesi, D.
AU - Ramirez-Cuesta, A. J.
AU - Zoppi, M.
PY - 2004/7/15
Y1 - 2004/7/15
N2 - We have measured the incoherent scattering function of liquid para-hydrogen, pure and mixed with neon, in various thermodynamic conditions, using inelastic neutron scattering. The experiments were carried out on TOSCA-II, a time-of-flight, inverse-geometry, crystal-analyzer spectrometer. After an accurate data reduction, the low-energy parts of neutron spectra recorded in forward scattering have been analyzed in the framework of the Gaussian approximation and fitted through a Levesque-Verlet model for the velocity auto-correlation function. Despite the excellent quality of these fits, the velocity auto-correlation function derived from the forward-scattering data appears totally unable to properly describe the backward-scattering ones. These findings prove a clear breakdown of the Gaussian approximation in these semi-quantum liquids.
AB - We have measured the incoherent scattering function of liquid para-hydrogen, pure and mixed with neon, in various thermodynamic conditions, using inelastic neutron scattering. The experiments were carried out on TOSCA-II, a time-of-flight, inverse-geometry, crystal-analyzer spectrometer. After an accurate data reduction, the low-energy parts of neutron spectra recorded in forward scattering have been analyzed in the framework of the Gaussian approximation and fitted through a Levesque-Verlet model for the velocity auto-correlation function. Despite the excellent quality of these fits, the velocity auto-correlation function derived from the forward-scattering data appears totally unable to properly describe the backward-scattering ones. These findings prove a clear breakdown of the Gaussian approximation in these semi-quantum liquids.
KW - Inelastic neutron scattering
KW - Liquid hydrogen and neon
KW - Velocity auto-correlation
UR - http://www.scopus.com/inward/record.url?scp=23044461461&partnerID=8YFLogxK
U2 - 10.1016/j.physb.2004.03.295
DO - 10.1016/j.physb.2004.03.295
M3 - Article
AN - SCOPUS:23044461461
SN - 0921-4526
VL - 350
SP - e1083-e1086
JO - Physica B: Physics of Condensed Matter
JF - Physica B: Physics of Condensed Matter
IS - 1-3 SUPPL. 1
ER -