Current restrictions in the elements that grade handles.

• grade uses quantum chemical geometry optimization in addition to the Mogul method. The current version of grade and consequently the Grade Web Server currently uses a helper based on fdynamo for semi-empirical quantum chemical calculations. This can only handle elements in the table below.

RM1	H C N O F P S Cl Br I
PM3	H Be C N O F Na Mg Al Si P S Cl K Zn Ga Ge As Se Br Cd In Sn Sb Te I Hg Tl Pb Bi
AM1	H Li Be B C N O F Na Mg Al Si P S Cl K Zn Br I

• RM1 is used in preference to AM1 or PM3
• these restrictions are temporary - other quantum chemical methods can handle all elements. These will be supported soon.

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Page by Oliver Smart and Tom Womack original version 05 March 2012. Address problems, corrections and clarifications to buster-develop@globalphasing.com