Hello again I have repeated the calculation using the low symmetry structure and i found a close results to those of the monoclinic one.
I have checked the wyckoof positions and the symmetry operations of the orthorhombic and the monoclinic structures and I have found that the later is a subgroup of the former and the only difference is the change of the lattice parameters and the atomic positions. Here is the low symmetry structure MnP-Pnma-afmIII2 P LATTICE,NONEQUIV.ATOMS: 4 MODE OF CALC=RELA unit=bohr 11.637501 6.731303 11.245005 90.000000 90.000000 90.000000 ATOM -1: X=0.00032814 Y=0.25000000 Z=0.24996705 MULT= 2 ISPLIT= 8 -1: X=0.99967186 Y=0.75000000 Z=0.75003295 Ni1 NPT= 781 R0=0.00005000 RMT= 2.25 Z: 28.0 LOCAL ROT MATRIX: 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 1.0000000 0.0000000 0.0000000 ATOM -2: X=0.50030217 Y=0.25000000 Z=0.25003393 MULT= 2 ISPLIT= 8 -2: X=0.49969783 Y=0.75000000 Z=0.74996607 Ni2 NPT= 781 R0=0.00005000 RMT= 2.25 Z: 28.0 LOCAL ROT MATRIX: 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 1.0000000 0.0000000 0.0000000 ATOM -3: X=0.25012913 Y=0.25000000 Z=0.58455708 MULT= 2 ISPLIT= 8 -3: X=0.74987087 Y=0.75000000 Z=0.41544292 S 1 NPT= 781 R0=0.00010000 RMT= 1.84 Z: 16.0 LOCAL ROT MATRIX: 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 1.0000000 0.0000000 0.0000000 ATOM -4: X=0.75011125 Y=0.25000000 Z=0.91545439 MULT= 2 ISPLIT= 8 -4: X=0.24988875 Y=0.75000000 Z=0.08454561 S 2 NPT= 781 R0=0.00010000 RMT= 1.84 Z: 16.0 LOCAL ROT MATRIX: 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 1.0000000 0.0000000 0.0000000 4 NUMBER OF SYMMETRY OPERATIONS -1 0 0 0.00000000 0-1 0 0.00000000 0 0-1 0.00000000 1 1 0 0 0.00000000 0 1 0 0.00000000 0 0 1 0.00000000 2 -1 0 0 0.00000000 0 1 0 0.50000000 0 0-1 0.00000000 3 1 0 0 0.00000000 0-1 0 0.50000000 0 0 1 0.00000000 4 Here is the monoclinic low symmetry structure NiS-MnP-afmIII P LATTICE,NONEQUIV.ATOMS: 4 11_P21/m MODE OF CALC=RELA unit=bohr 11.262961 10.563150 7.029377 90.000000 90.000000 90.000000 ATOM -1: X=0.25021227 Y=0.99991424 Z=0.25000000 MULT= 2 ISPLIT= 8 -1: X=0.74978773 Y=0.00008576 Z=0.75000000 Ni1 NPT= 781 R0=0.00005000 RMT= 2.13 Z: 28.0 LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 ATOM -2: X=0.75024661 Y=0.50012576 Z=0.75000000 MULT= 2 ISPLIT= 8 -2: X=0.24975339 Y=0.49987424 Z=0.25000000 Ni2 NPT= 781 R0=0.00005000 RMT= 2.13 Z: 28.0 LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 ATOM -3: X=0.08986359 Y=0.75012482 Z=0.75000000 MULT= 2 ISPLIT= 8 -3: X=0.91013641 Y=0.24987518 Z=0.25000000 S 1 NPT= 781 R0=0.00010000 RMT= 1.74 Z: 16.0 LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 ATOM -4: X=0.41013993 Y=0.25012471 Z=0.75000000 MULT= 2 ISPLIT= 8 -4: X=0.58986007 Y=0.74987529 Z=0.25000000 S 2 NPT= 781 R0=0.00010000 RMT= 1.74 Z: 16.0 LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000 1.0000000 4 NUMBER OF SYMMETRY OPERATIONS 1 0 0 0.00000000 0 1 0 0.00000000 0 0 1 0.00000000 1 -1 0 0 0.00000000 0-1 0 0.00000000 0 0 1 0.50000000 2 -1 0 0 0.00000000 0-1 0 0.00000000 0 0-1 0.00000000 3 1 0 0 0.00000000 0 1 0 0.00000000 0 0-1 0.50000000 4 The results are as follows respectively AFMIII2 Equation of state: Birch-Murnaghan info 2 E = E0 + 9/16*(B/14703.6)*V0*[(eta**2-1)**3*BP + (eta**2-1)**2*(6-4*eta**2)] --> eta = (V0/V)**(1/3) Pressure = 3/2*B*(eta**7 - eta**5)*(1 + 3/4*(BP-4)*[eta**2 - 1]) V0,B(GPa),BP,E0 760.8174 104.6494 4.1456 -15359.539382 vol energy de(Birch-Murnaghan) Pressure(GPa) 762.9081 -15359.539337 -0.000025 -0.286 739.3131 -15359.536947 -0.000163 3.184 715.7179 -15359.528892 0.000074 7.259 880.8836 -15359.487014 0.000040 -11.327 786.5033 -15359.536637 0.000170 -3.244 810.0984 -15359.529313 0.000130 -5.768 833.6935 -15359.517895 -0.000258 -7.922 857.2887 -15359.503959 0.000032 -9.760 Sigma: 0.000136 AFMIII Equation of state: Birch-Murnaghan info 2 E = E0 + 9/16*(B/14703.6)*V0*[(eta**2-1)**3*BP + (eta**2-1)**2*(6-4*eta**2)] --> eta = (V0/V)**(1/3) Pressure = 3/2*B*(eta**7 - eta**5)*(1 + 3/4*(BP-4)*[eta**2 - 1]) V0,B(GPa),BP,E0 755.1004 104.2740 3.9091 -15359.563916 vol energy de(Birch-Murnaghan) Pressure(GPa) 654.2035 -15359.503937 0.000401 19.797 633.9704 -15359.472984 0.000631 25.661 613.7373 -15359.432112 -0.000393 32.413 755.3690 -15359.563593 -0.000322 -0.037 775.6021 -15359.562384 0.000357 -2.651 795.8352 -15359.556773 0.000006 -4.944 816.0684 -15359.548718 0.000169 -6.957 836.3015 -15359.537517 -0.000217 -8.723 674.4366 -15359.526506 -0.000678 14.691 694.6697 -15359.544094 -0.000172 10.238 714.9029 -15359.555599 -0.000020 6.348 735.1359 -15359.562197 0.000237 2.944 Sigma: 0.000361 Best regards
_______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html