Dear Izaak Williamson, I believe the most important thing to be included is the magnetisation for the isolated N atom, something I am not sure if you included it or not. Attached you will find your input slightly changed for the N2 molecule and the N atom. The cohesive energy obtained with this input was 10eV. I hope it helps!
Fabio Negreiros IPCF - CNR Pisa, Italy -----Original Message----- From: Izaak Williamson <[email protected]> To: pw_forum at pwscf.org Sent: Tue, May 3, 2011 6:54 pm Subject: [Pw_forum] Cohesive Energy of N2 molecule Dear all, I am trying to calculate the cohesive energy of the N2 molecule using the attached input file (relax.in) and am getting a value of -16.57 eV. I use DFT with GGA and the pseudo-potential N.pbe-rrkjus.UPF. Other work [Fuchs et. al., Phys. Rev. B 65, (2002)245212] has performed similar calculations and obtained values ~10.5 eV. They even list an experimental value of 9.76 eV. Why is my value so much higher? Is there anything in my input file that could be giving inaccurate results? Is it my pseudo-potential that is causing this problem? Thanks for any help. -- Izaak Williamson Research Assistant Physics Department Boise State University _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20110503/b30e387f/attachment-0001.htm -------------- next part -------------- A non-text attachment was scrubbed... Name: N.in Type: application/octet-stream Size: 629 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110503/b30e387f/attachment-0004.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: N2.in Type: application/octet-stream Size: 682 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110503/b30e387f/attachment-0005.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: N.out Type: application/octet-stream Size: 13713 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110503/b30e387f/attachment-0006.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: N2.out Type: application/octet-stream Size: 35792 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20110503/b30e387f/attachment-0007.obj
