Re: [AMBER] QM/MM dynamics: metal oxides

From: David Case <>
Date: Sat, 26 Jan 2019 15:18:27 +0000

On Fri, Jan 25, 2019, emanuele falbo wrote:

>Sorry , I meant that the dynamics fails when the M solute molecule and 15
>Li ions are both treated with semi-empirical PM6, whereas the water at MM
>level .

First: there is (I think) no reason to treat Li+ ions as quantum
mechanical. Are you expecting any electron transfer from the metal?

Second: there is a good reason not to do this: the QM/MM code is
designed for a compact QM region. As I understand it, your Li ions may
move all over the place.

Finally: you are correct in noting that SCF failures can be hard to fix,
especially with a highly negative charge. The Reference Manual has some
suggestions of things to try. But handling metal oxides (as opposed to
organic molecules) may require considerable experimentation.

...good luck...dac

AMBER mailing list
Received on Sat Jan 26 2019 - 07:30:02 PST
Custom Search