[gmx-users] pme algorithm

[王珍]

Hi all,
 
      I used Gromacs run the biological system, which contains water, ions(Na+,Cl-), and nucleic. I used gromacs run the system, and the coulombtype was PME and the cutoff was 10 angstrom, then I want to use the commond rerun to calculate the interaction of resid 1 and resid 2, I add the energygrps in my mdp, and the coulombtype was PME, the .edr file can be obtained. Then I use g_energy to calculate the coulomb interaction. 

In real space, the coulomb energy using the equation  ,if using the equation  , are these two values different too much?




thank you very much.