. Author manuscript; available in PMC: 2018 Jun 21.
Published in final edited form as: Chem Phys Lett. 2016 Mar 19;651:243–250. doi: 10.1016/j.cplett.2016.03.010
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).