Dear Roberto Thanks for your reply. Yea,I have optimized the structure before. The basis.fdf contains the following parameter, that I have taken from siesta documentation. %block PAO.Basis C 3 0.01 n=2 0 2 E 69.86 4.68 6.004 4.195 1.000 1.000 n=2 1 2 E 18.95 3.78 4.995 3.100 1.000 1.000 n=3 2 1 E 16.84 0.05 4.187 1.000 %endblock PAO.Basis %block PAO.Basis H 2 0.22 n=1 0 2 E 2.07 0.00 4.971 1.771 1.000 1.000 n=2 1 1 E 0.89 0.01 4.988 1.000 %endblock PAO.Basis
------------------------------------------------------ Please suggest me for this deviation. Regards Saikat Paik > > Hi, > > Let me ask a silly question: did you optimized your CH_4 before the FC calculation ?. > At first sight your running parameters look pretty conservative to me, they should be fine. However those forces you mention must be the same (but for sign or course). > > What is that "PAO.Basis<basis.fdf" ?. No complaints about it ?. According to the manual it should be "%block PAO.Basis < basis.fdf". > > Regards, > > Roberto > > On Fri, 2 Nov 2012, [email protected] wrote: > >> Dear all >> >> In case phonon calculation of methane, I got the following >> frequencies. >> >> >> -5167.7290 -1034.5158 -608.1908 -608.1117 -67.8524 -67.8411 -23.1827 -0.3640 -0.0552 0.1225 1253.0287 2962.9873 2989.7891 3311.1902 3311.2054 >> >> >> >> Again in *.FC calculation, forces on the methane atoms for +x and -x displacement of atom no-1 are as follows. >> ----------------------------------------- >> For -x displacement >> 1 1.301549 -0.000023 0.000003 >> 2 -0.750276 0.000005 0.000000 >> 3 0.058844 0.004557 0.000000 >> 4 -0.670075 -0.000003 -0.000001 >> 5 0.058833 -0.004936 -0.000001 >> >> For +x displacement >> 1 -1.301586 -0.000026 -0.000002 >> 2 0.669685 0.000006 0.000000 >> 3 -0.058834 0.004552 0.000000 >> 4 0.749907 -0.000003 -0.000001 >> 5 -0.058837 -0.004934 -0.000001 >> ------------------------------------------ >> >> Here forces on 2nd and 4th atom have difference force. >> Are these will be same in + and - displacement of the atom? >> >> >> For *.FC calculation may input file as given. >> ----------------------------------------------------- >> # GGA >> # Phonon 32 atom >> # Methane >> >> SystemName Bond length calculation # Descriptive name of the system >> SystemLabel Methane # Short name for naming files >> >> # Output options >> >> LongOutput true >> >> # Species and atoms >> %block ChemicalSpeciesLabel >> 1 6 C >> 2 1 H >> %endblock ChemicalSpeciesLabel >> >> NumberOfSpecies 2 >> NumberOfAtoms 5 >> >> WriteKpoints true >> >> >> PAO.Basis<basis.fdf >> >> >> LatticeConstant 1 Ang >> %block LatticeVectors >> 10.0009892951 -0.000000035 -0.000000083 >> -0.000000035 10.0009892778 -0.000000094 >> -0.000000083 -0.000000094 10.0000562322 >> %endblock LatticeVectors >> Meshcutoff 500 Ry >> Kgridcutoff 50.0 Ang >> xc.functional GGA # Exchange-correlation functional xc.authors PBE >> MaxSCFIterations 500 # Maximum number of SCF iter DM.UseSaveDM true >> MD.TypeOfRun FC # Type of dynamics: >> MD.NumCGsteps 500 >> DM.Tolerance 0.1d-4 >> DM.Require.Energy.Convergence true >> DM.Energy.Tolerance 0.1d-4 eV >> #Atomic coordinates >> AtomicCoordinatesFormat Ang >> %block AtomicCoordinatesAndAtomicSpecies >> 05.00000000 05.00000000 05.00000000 1 >> 03.89716380 05.00000000 05.00000000 2 >> 05.00000000 03.89716380 05.00000000 2 >> 06.1028361 05.00000000 05.00000000 2 >> 05.00000000 06.1028361 05.00000000 2 >> %endblock AtomicCoordinatesAndAtomicSpecies >> >> >> ------------------------------------ >> >> >> >> Please help me what is going wrong. >> >> Thanking you. >> >> >> >> Regards >> Saikat Paik >> IIT Kanpur >> Mtech >> Mechanical Engineering. >> >> >
