  We investigate the influence of the autoionizing 3s3p(6)nl resonances on the
fifth harmonic generated by 200 - 240 nm laser fields interacting with Ar. To
determine the influence of a multi-electron response we have developed
capability within time dependent R-matrix theory to determine the harmonic
spectra generated. The fifth harmonic is affected by interference between the
response of a 3s electron and the response of a 3p electron, as demonstrated by
the asymmetric profiles in the harmonic yields as functions of wavelength.
