Hi Caitlin!
Is there any reason why you can't use the amber parameters? Peng-Fei Li recently published some really nice parameters for a non-bonding of different divalent cations, including calcium. They are now integrated into amber 14, and as far as I remember, you just need to source a specific ions leaprc file.
Peng-Fei just explained to me the whole process of using them via the amber mailing list, so if you other do a search for me or, better yet, for him, I'm sure you will find what you need.
Hope this helps,
Manuel
P.S. Here are his two publications
http://dx.doi.org/10.1021/ct400146w
http://dx.doi.org/10.1021/ct400751u
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Received on Fri Nov 28 2014 - 19:30:02 PST
