<p>Dear cp2k community, I hope you’re all doing well. </p><p>I’m writing to ask for clarification on the choice of the cutoff radius <span aria-hidden="true">R_CUTOFF​</span> parameter when using periodic boundary conditions in VDW_POTENTIAL in AIMD and geometry/cell optimizations:</p><p>      &VDW_POTENTIAL<br />         POTENTIAL_TYPE PAIR_POTENTIAL<br />         &PAIR_POTENTIAL<br />            PARAMETER_FILE_NAME dftd3.dat<br />            TYPE DFTD3<br />            REFERENCE_FUNCTIONAL PBE<br />            <span style="background-color: yellow;">R_CUTOFF [angstrom] 10</span><br />         &END<br />      &END VDW_POTENTIAL<br /></p><p>Suppose I have a cubic simulation box with side length <span aria-hidden="true">L = 5</span> angstrom, and I (mistakenly) set R_CUTOFF​ = 10 angstrom. Would setting RCUTOFF​ = 10 angstrom in a 5 angstrom cubic box cause the cutoff sphere to extend beyond the primary cell and overlap with periodic images, resulting in unphysical, multiply-counted interactions?</p><p>My understanding from classical MD is that we must obey the minimum-image convention, which requires R_CUTOFF​ ≤ 2 Lmin​​. I don't know if R_CUTOFF has this physical meaning of classical MD.</p><p>Thank you very much for your time and insights. </p><p>Best,</p><p>Emerson</p><p><br /></p>

<p></p>

-- <br />
You received this message because you are subscribed to the Google Groups "cp2k" group.<br />
To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>.<br />
To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/0afee8cd-252c-4c9e-b0c1-e2142551930bn%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/0afee8cd-252c-4c9e-b0c1-e2142551930bn%40googlegroups.com</a>.<br />