<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: courier new,courier,monaco,monospace,sans-serif; font-size: 12pt; color: #000000'><br><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><div style="font-family: courier new,courier,monaco,monospace,sans-serif; font-size: 12pt; color: #000000">Hello,<br><br>This email is directed mainly to Alan, who created Acpype.<br><br>I've noticed that Acpype has assigned dihedral constants as 0.65084 for many dihedrals of the form X -c3-n4-X, X -c3-c3-X, and others, in my generated GROMACS .itp files. These dihedrals have values of 1.400 in the amber 99sb .dat file, which should have instead given 1.4*4.184 = 5.858 for the result.<br><br>Most other dihedrals I've checked have behaved normally and their values correspond to what would be expected - except for dihedrals with values of 0.65084 in the .itp files.<br><br>Any ideas about what's going on?<br><br>Thanks for your time.<br><br>Kyle Greenway<br><br><br> <br></div></div><br></div></body></html>