This convolution model redshifts a multiplicative model. It takes the calculated model and shifts energies by 1/(1+z).
The energies command must be to used to extend the maximum energy over which the model is being calculated to (1+z) times the maximum energy in the response.
The parameter is:
An example model use is:
XSPEC> model phabs * (zmshift*phabs) * pow
which multiplies the power-law by both a redshifted and local absorption.