INTErpolation_scheme <Linear,None,Polynomial> :

This keyword defines the molecular transform interpolation scheme used by QS. The program supports three modes : a polynomial 4th order interpolation mode, a linear interpolation mode, and a nearest grid point non-interpolating mode. Polynomial interpolation is the most accurate of the three but it slows down the program by a factor of two and the gain in accuracy is not sufficient to justify using it as the default. The nearest grid point mode is the fastest and least accurate. If you are sampling the molecular transform finely enough (with, say, SCALE 8.0 or higher) you can use INTErpolation_scheme NONE safely. Having said these, I would suggest that you stick to INTErpolation_scheme LINEAR which is both fast and accurate for values of SCALE down to 4.0. Default is LINEAR.