Dear MS Community,

I’m working with a molecule whose initial torsion angle is 2.2°. However, when I use the Amorphous Cell module to pack multiple copies of this molecule into a periodic cell, that torsion angle changes. I confirmed this by extracting a single molecule from the .xtd file, and measuring its dihedral. I’ve tried various options, but can’t preserve the 2.2° torsion during packing or the subsequent geometry optimization. My goal is to lock this torsion angle in both the Amorphous Cell construction and the geometry optimization step, yet allow it to evolve freely during the Forcite molecular dynamics run. Could anyone advise how to enforce a fixed torsion angle during packing and optimization in Materials Studio?