Gas electron diffraction data: A representation of improved resolution in the frequency domain, a background correction for multiplicative and additive errors, and the effect of increased exposure of the photographic plates

Abstract An improved version of the previously proposed modified autocorrelation power spectrum is described. The enhanced resolution of this spectrum in the frequency domain is demonstrated for lead tetrachloride and benzene data. A background which may simultaneously correct gas electron diffraction data for both multiplicative and additive long periodic (low frequency) errors is suggested. Application of this background revealed systematic non-constant multiplicative errors in our data. The multiplicative corrections previously done to the calculated intensities of lead tetrachloride by modifications of the Pb scattering factor could now be substituted by a multiplicative background correction to the experimental intensities. For weakly exposed benzene data, the applied ‘blackness correction’ seemed to introduce a linear multiplicative correction of negative slope. The need for this correction disappeared for benzene data when the exposure of the photographic plates was increased.