Inelastic Neutron Scattering from a LiquidHe3-He4Mixture

We report inelastic-neutron-scattering measurements on liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}_{0.05}^{}{}_{}{}^{}$ ${}_{}{}^4{}_{}{}^{}\mathrm{He}_{0.95}^{}{}_{}{}^{}$ in the $Q$ region from 0.8 to 2.3 ${\mathrm{\AA }}^{-1\mathrm{}}$ at 1.6 K. The shifts and increases in natural linewidth of the single excitation peaks relative to pure ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at the same temperature were determined by a least-squares fitting procedure. The shifts vary from a small, possibly negative, value at the roton minimum to positive values around 0.5 K at both ends of the $Q$ range. The full widths at half-maximum of the extra broadening vary from 0.5 to 1.5 K over the same range.