A comparison of two methods for the calculation of pseudorotation parameters

A comparison of the two methods available for the calculation of exact values of pseudorotation parameters P, τ_m, i.e. the Fourier-series (FS) method [Rao, Westhof & Sundaralingam (1981). Acta Cryst. A37, 421-425] and the least-squares (LS) method [Jaskólski (1983). J. Chem. Educ. 60, 980-981] reveals that they yield identical values for τ_m and P. The variances σ²(τ_m) and σ²(P) calculated by these methods are, however, different since they have different interpretations.