Isolated multipole echoes for study of anisotropic moment collision kernels

Isolated-multipole-moment photon-echo techniques for atomic collision studies are described and analyzed. The techniques employ three-pulse photon echoes observed in a polarization rotation configuration such that the echo intensity depends on the square of an isolated J=1 multipole moment for which the velocity-changing kernel is diagonal. This scheme is applied to resolve clearly classical and wave-mechanical features of ³P₁ orientation kernels for ¹⁷⁴gas scattering. The diagonality (in the sense to be described) of the one-dimensional kernels chosen for study is discussed physically and derived in detail.