Hello all, I'm applying the principle of interpolation in order to find the buckling angle in a similar system to the lead titanate example. And though I'm sure that my path.dat list contains paths of identical reff, my generated feffNNNN.dat files are changing the path lengths for beta=0 and beta=20. I think it has something to do with rounding in feff - am i right? See below - FEFF1019 = beta 0 degrees, FEFF2019 = beta 20 degrees, and relevant part of paths.dat file. Thanks for your assistance! Joseph ---------------> FROM FEFF2019.dat 4 4.000 5.9211 3.6223 -3.72616 nleg, deg, reff, rnrmav(bohr), edge x y z pot at# 0.0000 0.0000 0.0000 0 32 Ge absorbing atom 0.0000 -2.9590 0.0000 1 52 Te 0.0000 -5.7395 -1.0213 2 51 Sb 0.0000 -2.9590 0.0000 1 52 Te ------------------> FROM FEFF1019.dat 4 4.000 5.9179 3.6223 -3.72616 nleg, deg, reff, rnrmav(bohr), edge x y z pot at# 0.0000 0.0000 0.0000 0 32 Ge absorbing atom 0.0000 -2.9590 0.0000 1 52 Te 0.0000 -5.9179 0.0000 2 51 Sb 0.0000 -2.9590 0.0000 1 52 Te -------------------------------> FROM PATHS LIST 1019 4 4.000 index, nleg, degeneracy, r= 5.9179 x y z ipot label rleg beta eta 0.000000 -2.958950 0.000000 1 'Te ' 0.000000 -5.917900 0.000000 2 'Sb ' 0.000000 -2.958950 0.000000 1 'Te ' 0.000000 0.000000 0.000000 0 'Ge ' 2019 4 4.000 index, nleg, degeneracy, r= 5.9179 x y z ipot label rleg beta eta 0.000000 -2.958950 0.000000 1 'Te ' 0.000000 -5.739453 -1.021255 2 'Sb ' 0.000000 -2.958950 0.000000 1 'Te ' 0.000000 0.000000 0.000000 0 'Ge ' -- Joseph Washington Research Assistant Department of Physics North Carolina State University 431 Riddick Hall Raleigh, NC 27695-8202 email: jswashin@ncsu.edu