Impulse approximationNNamplitudes for proton-nucleus interactions

Transformations of nucleon-nucleon amplitudes from the center of mass frame to the proton-nucleus Breit frame are developed for use in multiple scattering analyses. As a by product, a matrix equation is given for the invariant $\mathrm{NN}$ amplitudes in Dirac spinor representation. Based on recent $\mathrm{NN}$ phase shifts, Gaussian parametrization of the $\mathrm{pp}$ and $\mathrm{np}$ amplitudes are calculated and some proton-nucleus calculations are presented to illustrate the effects of the Breit frame amplitudes. For ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, these effects are quite small.