I am modeling the Debye-Waller factor by using the Einstein model in Artemis, where the Einstein temperature (thetae) is a guess parameter and sigma2 is a defined parameter as eins(temperature, thetae). Although, after running the fit, the error for the estimation of thetae is given by the fit report, the error for the corresponding defined sigma2 is missing. I am working on some models to reduce the errors in the estimation of the Debye-Waller factor, so it's an important value for my research. I tried to propagate the errors by using the equation in the ref paper (E. Sevillano, H. Meuth, and J. J. Rehr. Extended x-ray absorption fine structure Debye-Waller factors. I. Monatomic crystals. Phys. Rev. B, 20:4908–4911, Dec 1979. doi:10.1103/PhysRevB.20.4908.) However, I cannot obtain the same value of sigma2 when I substitute thetae into the equation from the paper compared to the value reported in the fit. Can anyone help clarify the equation (or script) used in Artemis? Thank you! Wilson Henao