#Input file for the anaddb code. Analysis of the Si DDB #Flags ifcflag 1 ! Interatomic force constant flag thmflag 1 ! Thermal flag. Gives Internal energy, entropy, ! heat capacity, phonon DOS, Debye-Waller factor) #Interatomic force constant info dipdip 0 ! No explicit dipole-dipole treatment ifcana 1 ! Analysis of the IFCs ifcout 20 ! Number of IFC's written in the output, per atom natifc 1 ! Number of atoms in the cell for which ifc's are analysed atifc 1 ! List of atoms #Thermal information nchan 800 ! # of channels for the DOS with channel width 1 cm-1 nwchan 10 ! # of different channel widths from this integer down to 1 cm-1 thmtol 0.2 ! Tolerance on thermodynamical function fluctuations # Use standard set of temperatures (default for ntemper, tempermin, temperinc) #Wavevector grid number 1 (coarse grid, from DDB) brav 2 ! Bravais Lattice : 1-S.C., 2-F.C., 3-B.C., 4-Hex.) ngqpt 8 8 8 ! Monkhorst-Pack indices nqshft 1 ! number of q-points in repeated basic q-cell q1shft 0.5 0.5 0.5 #Wavevector grid number 2 (series of fine grids, extrapolated from intrat forces) ng2qpt 24 24 24 ! sample the BZ up to ngqpt2 ngrids 6 ! number of grids of increasing size q2shft 0.5 0.5 0.5 #Wavevector list number 1 (Reduced coordinates and normalization factor) nph1l 4 ! number of phonons in list 1 qph1l 0.0 0.0 0.0 1.0 ! (G point) 0.5 0.0 0.0 1.0 ! (L point) 0.5 0.5 0.0 1.0 ! (X point) 0.5 0.5 0.5 1.0 ! (L point again) #%% #%% [setup] #%% executable = anaddb #%% test_chain = t16.abi, t17.abi #%% [files] #%% files_to_test = #%% t16.abo, tolnlines = 0, tolabs = 0.000e+00, tolrel = 0.000e+00 #%% extra_inputs = t16.ddb.in.gz #%% [paral_info] #%% max_nprocs = 4 #%% [extra_info] #%% keywords = #%% authors = Unknown #%% description = #%% Analyze a DDB for Silicon. Lattice parameter = 10.18 Angstrom. #%% Here, IFCs are obtained, and can be compared to those #%% published in Table I of Rignanese et al, PRB53, 4488 (1996). #%% For example, the atoms numbers for NN=0,1,2,5 in Table I #%% are found as atoms 1,5,17,20. The numbers are equal in the #%% paper or in the output of the code. #%% The frequencies at X and L points are also computed. They #%% can be compared with those provided in TABLE II (TA(X) mode #%% at 140.466 cm-1) and TABLE III (TA(L) mode at 108.626 cm-1) #%% in the above-mentioned paper. The numbers are equal in the #%% paper or in the output of the code. #%% Thermodynamic quantities are also obtained. The input #%% parameters of the code does not give particularly well #%% converged quantities (one needs reasonable CPU time for testing !), #%% but it is OK for comparison with the paper. #%% In the output of the code, a mole corresponds #%% to the number of Avogadro times one CELL. As a Silicon cell contains #%% 2 atoms, caution must be taken in the comparison with experiment ! #%% We will refer to the numbers given by the code as being given #%% for a mole-cell (in short a mol-c). The distinction between #%% the usual definition of a mole (Avogadro number times 1 #%% Silicon atom) and a mole-cell (Avogadro number times 2 Silicon atom) #%% was unfortunately the source of errors in the paper by #%% Rignanese et al (our thanks to Steve Erwin for noticing #%% this - an errata should be written). From the output of the code #%% ( zero Kelvin is approximated by results at 1 Kelvin) : #%% the zero point contribution to the Helmholtz free energy #%% is 11.90 kJ/mol-c , so 5.95 kJ/mole ; the entropy at 298.15K #%% is 38.25 J/(mol-c.K), so 19.12 J/(mole.K) ; the constant-volume #%% specific heat at 298.15K is 39.59 J/(mol-c.K), so 19.80 J/(mole.K) ; #%% the change in F (Helmholtz free energy) from 1 K to 298.15 K is #%% -4.91 kJ/mol-c, so -2.45 kJ/mole ; the change in E (internal energy) #%% from 1 K to 298.15 K is 6.49 kJ/mol-c, so 3.25 kJ/mole. Supposing #%% that we take the usual definition of a mole (Avogadro number times 1 #%% Silicon atom), then, in the above-mentioned paper, the FIG. 3, 5 and 8 #%% should be rescaled, as well as the zero-point contribution to the #%% Helmholtz free energy (5.95 kJ/mole, and not 12 J/mole - the 'k' was #%% also missing), that is only 1.25% of the cohesive energy. #%% The output of the code is now more clear than in 1995, and this #%% kind of error should not appear anymore. #%% topics = Phonons, PhononBands, Temperature #%%