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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'>Hello,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'> I may be encountering a bug in vers. 6.4.1 in connection with relaxation using vdW-TS. The attached files contain input and output for 2 different runs looking at adsorption of NO2 on an MoS2 monolayer. Everything is the same (I believe), and the input structures are very similar. In fact, the input to #245329 is the final-step output from #244653. The one (known) difference is that #244653 uses 140/560 cut-offs and #245329 uses 100/400 cut-offs. The disturbing finding is that the TS dispersion corrections are very different for the two (approximately -0.71925 Ryd for one and -0.72919 Ryd for the other). This is playing havoc with my attempts to obtain adsorption energies. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'> I've done similar comparisons for different cut-offs in other runs using vers. 6.2 and 6.4.1 and not seen differences anywhere near this large, except in one case where it may have been half this big. In other words, these large differences in TS dispersion corrections for nominally-similar conditions appear to be sporadic. I should add that I've tested the Hamann ONCV pseudopotentials that I'm using and find that they give very good results for my systems of interest. I've also tested the convergence with respect to the Monkhorst Pack grid, and that's very good. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'> One other point, if I may. The 6.4 release notes say that vc-relax with TS wasn't working in earlier versions. Before being made aware of this I was using vc-relax with TS in vers. 6.2 with no obvious problems. The stress, forces and total energy all converged nicely, and the final scf (when it didn't crash) was very close to the last vc step. In what way was vc-relax + TS not working in vers. 6.2 ? <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'> Any information, especially advice about a work-around if this is a real bug, would be greatly appreciated. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'>Best Wishes,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'>Vic Bermudez<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;font-family:"Arial",sans-serif'><a href="mailto:bermudez@alum.mit.edu">bermudez@alum.mit.edu</a> <o:p></o:p></span></p></div></body></html>