Dear SIESTA users,
I am very new to the SIESTA code, so to start with I am familiarising myself with the protocols involved to run calculations with the code. I am trying to reproduce some numbers from a paper, where a crystal structure (triclinic system) of a Ru-allyl complex was relaxed (Organometallics, 2013, 32, 3784). I have set up a SIESTA input for relaxing this structure, using PBE with the default DZP basis sets for all atoms, along with pseudopotentials from the SIESTA database (I am aware that this might not be the best choice, but to start with it might be a fair option). The calculation seems to fail to converge to a minimum structure and stops after the default 500 opt cycles. This makes me suspicious, since my feeling is that the structure should have converged within 500 cycles. The SCF cycles converge fine. I have attached my input file below, the structure is read in from an external xyz file (attached). I have used as many default settings for the moment as possible. I would appreciate if you could share your experience and advice on this subject. Is such an input in principle a good starting point for the task at hand? What could I improve? Would the use of a Monkhorst-Pack grid be a better choice? There are some other Questions regarding dispersion corrections but first I need to play around with what I understand from the manual. Kind regards, thanks for everybody's help. Really trying to learn how to get reliable results. Tobias SystemName [Ru(AcCN)2(Cp*)(eta3-phenylallyl) unit cell SystemLabel ru_allyl NumberOfAtoms 160 NumberOfSpecies 7 WriteMullikenPop 1 %block ChemicalSpeciesLabel 1 44 Ru # Species index, atomic number, species label 2 15 P 3 9 F 4 8 O 5 7 N 6 6 C 7 1 H %endblock ChemicalSpeciesLabel MeshCutoff 400.0 Ry NetCharge 0.00 XC.functional GGA XC.authors PBE SpinPolarized .false. DM.NumberPulay 4 DM.MixingWeight 0.3 DM.UseSaveDM .true. NeglNonOverlapInt False AtomicCoordinatesFormat NotScaledCartesianAng AtomicCoordinatesAndAtomicSpecies < ru_allylinput.xyz LatticeConstant 1.0 Ang %block LatticeParameters 9.5347 11.7495 15.8787 109.395 96.719 100.965 %endblock LatticeParameters WriteCoorXmol True WriteForces .true. WriteMullikenPop 1 SaveDeltaRho .true. MD.TypeOfRun cg # Type of dynamics: Conjugate gradients MD.NumCGsteps 500 # number of CG steps MD.MaxCGDispl 0.15 Ang MD.MaxForceTol 0.04 eV/Ang MD.UseSaveXV yes MD.VariableCell .true. ________________________________ Dr. Tobias Kraemer Research Associate Institute of Chemical Sciences School of Engineering & Physical Sciences Heriot-Watt University Edinburgh EH14 4AS United Kingdom * [email protected] * +44 (0)131 451 3259 ________________________________ ----- Sunday Times Scottish University of the Year 2011-2013 Top in the UK for student experience Fourth university in the UK and top in Scotland (National Student Survey 2012) We invite research leaders and ambitious early career researchers to join us in leading and driving research in key inter-disciplinary themes. Please see www.hw.ac.uk/researchleaders for further information and how to apply. Heriot-Watt University is a Scottish charity registered under charity number SC000278.
ru_allylinput.xyz
Description: ru_allylinput.xyz
ru_allyl.fdf
Description: ru_allyl.fdf
