Dear SIESTA guys,
I am trying to relax a big structure using CG and diag. At first few steps, it
looks pretty good, something like this:
siesta: iscf Eharris(eV) E_KS(eV) FreeEng(eV) dDmax Ef(eV)
siesta:1 -258035.2072 -258036.9370 -258036.9370 0.0275 -4.3651
siesta:2 -258036.2208 -258035.0256 -258035.0256 0.0112 -4.5080
siesta:3 -258035.1812 -258036.5612 -258036.5612 0.0218 -4.4097
siesta:4 -258035.1795 -258035.8834 -258035.8834 0.0112 -4.4638
siesta:5 -258035.1793 -258035.4838 -258035.4838 0.0049 -4.4687
siesta:6 -258035.1789 -258035.2657 -258035.2657 0.0015 -4.4613
siesta:7 -258035.1787 -258035.1951 -258035.1951 0.0003 -4.4550
siesta:8 -258035.1786 -258035.1827 -258035.1827 0.0001 -4.4527
however after several CG steps, the dDMax of the second step starts shooting
up:
siesta: iscf Eharris(eV) E_KS(eV) FreeEng(eV) dDmax Ef(eV)
siesta:1 -258041.6771 -258049.1974 -258049.1974 0.0445 -4.3312
siesta:2 -414986.5091 -257706.6909 -257706.6909 7.6328 -4.9342
siesta:3 -258044.3070 -258045.0301 -258045.0301 0.0782 -3.7154
siesta:4 -258037.8846 -258045.8548 -258045.8548 0.0263 -4.5521
siesta:5 -258037.6817 -258045.1416 -258045.1416 0.0244 -4.5881
siesta:6 -258037.5376 -258043.5246 -258043.5246 0.0203 -4.6387
siesta:7 -258037.4613 -258039.8974 -258039.8974 0.0113 -4.5536
siesta:8 -258037.4461 -258039.1308 -258039.1308 0.0090 -4.5065
siesta:9 -258037.4415 -258038.3142 -258038.3142 0.0050 -4.4399
siesta: 10 -258037.4422 -258037.8985 -258037.8985 0.0029 -4.4292
siesta: 11 -258037.4395 -258037.4958 -258037.4958 0.0010 -4.4607
siesta: 12 -258037.4387 -258037.5226 -258037.5226 0.0006 -4.4739
siesta: 13 -258037.4384 -258037.5255 -258037.5255 0.0004 -4.4780
siesta: 14 -258037.4383 -258037.5025 -258037.5025 0.0003 -4.4779
siesta: 15 -258037.4383 -258037.4524 -258037.4524 0.0001 -4.4761
and eventually dDMax of the second step becomes so big that it can never
converge:
siesta:1 -258060.4975 -258056.7123 -258056.7123 0.1295 -4.4799
siesta:2 -1304652.4483 -252914.3188 -252914.3188 20.6318-40.9257
siesta:3 -270662.4603 -258022.4392 -258022.4392 1.3946 -2.5632
siesta:4 -262389.1412 -258028.2383 -258028.2383 1.0408 -2.9631
siesta:5 -261346.4355 -258032.8542 -258032.8542 0.9443 -3.0476
siesta:6 -261008.6664 -258033.7068 -258033.7068 0.9124 -3.0832
siesta:7 -1415808.5682 -248461.9222 -248461.9222 8.0613
siesta:8 -1329228.9170 -249101.5407 -249101.5407 7.8758
siesta:9 -1389456.5404 -248138.9810 -248138.9810 7.9741
siesta: 10 -1490261.9252 -246579.3815 -246579.3815 8.0538
siesta: 11 -1720098.0877 -242387.2899 -242387.2899 8.0561
siesta: 12 -6743529.762738225.975738225.9757 21.0844
siesta: 13 -3691005.7503 -74168.3252 -74168.3252 16.3687
siesta: 14 -2226132.5093 -141461.1037 -141461.1037 12.2798
siesta: 15 -1669147.7537 -173101.0090 -173101.0090 7.9487-79.2650
siesta: 16 -1938495.5805 -183836.1974 -183836.1974 18.7913
I wonder if anyone knows why this could happen, and how can you get around it.
I use a Mixing parameter 0.08, 3 Pulay steps. I could set the mixing parameter
to a very small number, but it will take many steps to get SCF converged...
Thanks,
Cherry
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