[Pw_forum] pw 5.1.1 odd results in vc-relax

Giuseppe Mattioli giuseppe.mattioli at ism.cnr.it
Mon Feb 9 10:59:56 CET 2015


Dear Carlo
Your *very exotic* crystal structure is going to be challenging for every code for several reasons. I suppose that, for example, you will never obtain 
decent lattice parameters without using a (good) contribution to dispersion forces. As you are using PAW PPs, I suggest to try the new XDM method. I 
can report excellent results for (metal-)organic crystals. You must supply to the code the appropriate parameters, which in the case of PBE are

    vdw_corr='xdm',
    xdm_a1=0.3275, xdm_a2=2.7673,

It should probably not affect the structural properties very much, but you may try to check if the Iodine atoms benefit of some spin-orbit coupling 
treatment. 

The cell is small, and even if your bands should be not far from flat, you may experience some strong interaction between localized states at gamma. 
You can try to use a shifted k-points mesh (e.g., 2, 2, 2, 1, 1, 1) in scf calculations, and to reintroduce gamma in nscf ones if you need a DOS plot.

HTH
Giuseppe

On Sunday, February 08, 2015 12:10:25 AM Carlo Nervi wrote:
> Good point. I tried also with Castep 7.0 (same pbesol but onthe fly pseudo)
> and it cannot reach convergence. Just increase and eat RAM without reaching
> any convergence.
> Anyway, I run also the same two inputs also on the 4.3.2 version and the
> results are almost the same.  Below I report them for comparison.
> I'm confused....
> 
>      pw.x 5.1.1: ecut60_kp222_opt.out
>   pw.x 4.3.2: ecut60_kp222_opt_pw432.out
> [ 1] unit-cell volume          =    1834.6689 (a.u.)^3
>            [ 1]    =    1834.6689 (a.u.)^3
> [ 2] new unit-cell volume =   1916.92975 a.u.^3 (   284.05968 Ang^3 )   [
> 2]   1916.89038 a.u.^3 (   284.05384 Ang^3 )
> [ 3] new unit-cell volume =   1870.67155 a.u.^3 (   277.20492 Ang^3 )   [
> 3]   1870.65414 a.u.^3 (   277.20234 Ang^3 )
> [ 4] new unit-cell volume =   1921.05067 a.u.^3 (   284.67033 Ang^3 )   [
> 4]   1921.02565 a.u.^3 (   284.66663 Ang^3 )
> [ 5] new unit-cell volume =   1916.96334 a.u.^3 (   284.06466 Ang^3 )   [
> 5]   1916.80696 a.u.^3 (   284.04148 Ang^3 )
> [ 6] new unit-cell volume =   1901.29925 a.u.^3 (   281.74348 Ang^3 )   [
> 6]   1900.95704 a.u.^3 (   281.69277 Ang^3 )
> [ 7] new unit-cell volume =   1901.18545 a.u.^3 (   281.72661 Ang^3 )   [
> 7]   1901.00790 a.u.^3 (   281.70030 Ang^3 )
> [ 8] new unit-cell volume =   1900.12506 a.u.^3 (   281.56948 Ang^3 )   [
> 8]   1899.99088 a.u.^3 (   281.54960 Ang^3 )
> [ 9] new unit-cell volume =   1896.90561 a.u.^3 (   281.09241 Ang^3 )   [
> 9]   1896.77471 a.u.^3 (   281.07301 Ang^3 )
> [10] new unit-cell volume =   1890.33791 a.u.^3 (   280.11917 Ang^3 )
> [10]   1890.25923 a.u.^3 (   280.10751 Ang^3 )
> [11] new unit-cell volume =   1881.89664 a.u.^3 (   278.86831 Ang^3 )
> [11]   1882.03626 a.u.^3 (   278.88900 Ang^3 )
> [12] new unit-cell volume =   1873.99541 a.u.^3 (   277.69747 Ang^3 )
> [12]   1873.51712 a.u.^3 (   277.62659 Ang^3 )
> [13] new unit-cell volume =   1865.86498 a.u.^3 (   276.49266 Ang^3 )
> [13]   1866.51615 a.u.^3 (   276.58915 Ang^3 )
> [14] new unit-cell volume =   1864.19811 a.u.^3 (   276.24566 Ang^3 )
> [14]   1863.95891 a.u.^3 (   276.21021 Ang^3 )
> [15] new unit-cell volume =   1864.57674 a.u.^3 (   276.30176 Ang^3 )
> [15]   1864.53369 a.u.^3 (   276.29538 Ang^3 )
> [16] new unit-cell volume =   1865.55777 a.u.^3 (   276.44714 Ang^3 )
> [16]   1865.49744 a.u.^3 (   276.43820 Ang^3 )
> [17] new unit-cell volume =   1866.79207 a.u.^3 (   276.63004 Ang^3 )
> [17]   1866.65432 a.u.^3 (   276.60963 Ang^3 )
> [18] new unit-cell volume =   1869.30622 a.u.^3 (   277.00260 Ang^3 )
> [18]   1869.10349 a.u.^3 (   276.97256 Ang^3 )
> [19] new unit-cell volume =   1873.20777 a.u.^3 (   277.58075 Ang^3 )
> [19]   1872.78516 a.u.^3 (   277.51813 Ang^3 )
> [20] new unit-cell volume =   1879.19014 a.u.^3 (   278.46724 Ang^3 )
> [20]   1878.36245 a.u.^3 (   278.34459 Ang^3 )
> [21] new unit-cell volume =   1884.66187 a.u.^3 (   279.27807 Ang^3 )
> [21]   1883.96194 a.u.^3 (   279.17435 Ang^3 )
> [22] new unit-cell volume =   1891.20864 a.u.^3 (   280.24820 Ang^3 )
> [22]   1889.86635 a.u.^3 (   280.04930 Ang^3 )
> [23] new unit-cell volume =   1901.10293 a.u.^3 (   281.71439 Ang^3 )
> [23]   1898.71267 a.u.^3 (   281.36018 Ang^3 )
> [24] new unit-cell volume =   1914.72645 a.u.^3 (   283.73318 Ang^3 )
> [24]   1912.22947 a.u.^3 (   283.36317 Ang^3 )
> [25] new unit-cell volume =   1930.25095 a.u.^3 (   286.03368 Ang^3 )
> [25]   1924.28177 a.u.^3 (   285.14914 Ang^3 )
> [26] new unit-cell volume =   1937.73275 a.u.^3 (   287.14236 Ang^3 )
> [26]   1937.63927 a.u.^3 (   287.12851 Ang^3 )
> [27] new unit-cell volume =   1941.73622 a.u.^3 (   287.73562 Ang^3 )
> [27]   1941.66666 a.u.^3 (   287.72531 Ang^3 )
> [28] new unit-cell volume =   1944.88562 a.u.^3 (   288.20231 Ang^3 )
> [28]   1943.48926 a.u.^3 (   287.99539 Ang^3 )
> [29] new unit-cell volume =   1949.01818 a.u.^3 (   288.81469 Ang^3 )
> [29]   1945.65177 a.u.^3 (   288.31584 Ang^3 )
> [30] new unit-cell volume =   1953.99704 a.u.^3 (   289.55248 Ang^3 )
> [30]   1950.94524 a.u.^3 (   289.10025 Ang^3 )
> [31] new unit-cell volume =   1962.17319 a.u.^3 (   290.76406 Ang^3 )
> [31]   1958.81209 a.u.^3 (   290.26600 Ang^3 )
> [32] new unit-cell volume =   1974.45089 a.u.^3 (   292.58343 Ang^3 )
> [32]   1970.67480 a.u.^3 (   292.02387 Ang^3 )
> [33] new unit-cell volume =   1992.92859 a.u.^3 (   295.32154 Ang^3 )
> [33]   1988.56058 a.u.^3 (   294.67427 Ang^3 )
> [34] new unit-cell volume =   2020.13868 a.u.^3 (   299.35366 Ang^3 )
> [34]   2015.10118 a.u.^3 (   298.60718 Ang^3 )
> [35] new unit-cell volume =   2032.08995 a.u.^3 (   301.12466 Ang^3 )
> [35]   2026.74222 a.u.^3 (   300.33221 Ang^3 )
> [36] new unit-cell volume =   2049.78113 a.u.^3 (   303.74622 Ang^3 )
> [36]   2043.98629 a.u.^3 (   302.88751 Ang^3 )
> [37] new unit-cell volume =   2076.66366 a.u.^3 (   307.72980 Ang^3 )
> [37]   2069.87449 a.u.^3 (   306.72375 Ang^3 )
> [38] new unit-cell volume =   2100.27547 a.u.^3 (   311.22871 Ang^3 )
> [38]   2108.37862 a.u.^3 (   312.42947 Ang^3 )
> [39] new unit-cell volume =   2098.38435 a.u.^3 (   310.94848 Ang^3 )
> [39]   2103.73265 a.u.^3 (   311.74101 Ang^3 )
> [40] new unit-cell volume =   2096.76071 a.u.^3 (   310.70788 Ang^3 )
> [40]   2103.09452 a.u.^3 (   311.64645 Ang^3 )
> [41] new unit-cell volume =   2093.53470 a.u.^3 (   310.22983 Ang^3 )
> [41]   2105.36802 a.u.^3 (   311.98335 Ang^3 )
> [42] new unit-cell volume =   2090.92157 a.u.^3 (   309.84261 Ang^3 )
> [42]   2109.06268 a.u.^3 (   312.53084 Ang^3 )
> [43] new unit-cell volume =   2088.04282 a.u.^3 (   309.41602 Ang^3 )
> [43]   2114.58893 a.u.^3 (   313.34975 Ang^3 )
> [44] new unit-cell volume =   2087.37088 a.u.^3 (   309.31645 Ang^3 )
> [44]   2123.60310 a.u.^3 (   314.68551 Ang^3 )
> [45] new unit-cell volume =   2089.06128 a.u.^3 (   309.56694 Ang^3 )
> [45]   2137.26799 a.u.^3 (   316.71044 Ang^3 )
> [46] new unit-cell volume =   2092.69424 a.u.^3 (   310.10529 Ang^3 )
> [46]   2132.82626 a.u.^3 (   316.05224 Ang^3 )
> [47] new unit-cell volume =   2098.38075 a.u.^3 (   310.94794 Ang^3 )
> [47]   2127.74869 a.u.^3 (   315.29982 Ang^3 )
> [48] new unit-cell volume =   2104.49475 a.u.^3 (   311.85394 Ang^3 )
> [48]   2124.00032 a.u.^3 (   314.74437 Ang^3 )
> [49] new unit-cell volume =   2100.70529 a.u.^3 (   311.29240 Ang^3 )
> [49]   2117.12346 a.u.^3 (   313.72532 Ang^3 )
> [50] new unit-cell volume =   2083.40173 a.u.^3 (   308.72828 Ang^3 )
> [50]   2105.73130 a.u.^3 (   312.03718 Ang^3 )
> [51] new unit-cell volume =   2077.05453 a.u.^3 (   307.78772 Ang^3 )
> [51]   2088.74510 a.u.^3 (   309.52009 Ang^3 )
> [52] new unit-cell volume =   2070.02859 a.u.^3 (   306.74659 Ang^3 )
> [52]   2088.85865 a.u.^3 (   309.53691 Ang^3 )
> [53] new unit-cell volume =   2066.04858 a.u.^3 (   306.15681 Ang^3 )
> [53]   2088.20078 a.u.^3 (   309.43943 Ang^3 )
> [54] new unit-cell volume =   2061.21037 a.u.^3 (   305.43986 Ang^3 )
> [54]   2085.25660 a.u.^3 (   309.00314 Ang^3 )
> [55] new unit-cell volume =   2058.58741 a.u.^3 (   305.05118 Ang^3 )
> [55]   2080.16617 a.u.^3 (   308.24882 Ang^3 )
> [56] new unit-cell volume =   2054.42953 a.u.^3 (   304.43504 Ang^3 )
> [56]   2074.14518 a.u.^3 (   307.35660 Ang^3 )
> [57] new unit-cell volume =   2054.24848 a.u.^3 (   304.40821 Ang^3 )
> [57]   2064.48193 a.u.^3 (   305.92466 Ang^3 )
> [58] new unit-cell volume =   2053.77333 a.u.^3 (   304.33780 Ang^3 )
> [58]   2051.00842 a.u.^3 (   303.92809 Ang^3 )
> [59] new unit-cell volume =   2054.07492 a.u.^3 (   304.38250 Ang^3 )
> [59]   2041.14648 a.u.^3 (   302.46670 Ang^3 )
> [60] new unit-cell volume =   2058.59233 a.u.^3 (   305.05191 Ang^3 )
> [60]   2038.54028 a.u.^3 (   302.08050 Ang^3 )
> [61] new unit-cell volume =   2058.36374 a.u.^3 (   305.01803 Ang^3 )
> [61]   2040.74343 a.u.^3 (   302.40697 Ang^3 )
> [62] new unit-cell volume =   2058.36374 a.u.^3 (   305.01803 Ang^3 )
> [62]   2045.70626 a.u.^3 (   303.14239 Ang^3 )
> [63] unit-cell volume          =    2058.3637 (a.u.)^3
>           [63]   2045.70626 a.u.^3 (   303.14239 Ang^3 )
> 
>                            [64]    =    2045.7063 (a.u.)^3
> 
> 
> 
> And also:
> 
>   pw.x 5.1.1
>                         pw.x 4.3.2
> [ 1]  unit-cell volume          =    1960.1695 (a.u.)^3
>            [ 1]   =    1960.1695 (a.u.)^3
> [ 2]  new unit-cell volume =   1959.31994 a.u.^3 (   290.34126 Ang^3 )   [
> 2]  1959.25962 a.u.^3 (   290.33232 Ang^3 )
> [ 3]  new unit-cell volume =   1958.53703 a.u.^3 (   290.22524 Ang^3 )   [
> 3]  1958.24276 a.u.^3 (   290.18164 Ang^3 )
> [ 4]  new unit-cell volume =   1957.26194 a.u.^3 (   290.03629 Ang^3 )   [
> 4]  1956.83874 a.u.^3 (   289.97358 Ang^3 )
> [ 5]  new unit-cell volume =   1955.57715 a.u.^3 (   289.78663 Ang^3 )   [
> 5]  1954.97243 a.u.^3 (   289.69702 Ang^3 )
> [ 6]  new unit-cell volume =   1953.25606 a.u.^3 (   289.44268 Ang^3 )   [
> 6]  1952.34070 a.u.^3 (   289.30704 Ang^3 )
> [ 7]  new unit-cell volume =   1949.69460 a.u.^3 (   288.91493 Ang^3 )   [
> 7]  1949.10416 a.u.^3 (   288.82743 Ang^3 )
> [ 8]  new unit-cell volume =   1947.54165 a.u.^3 (   288.59589 Ang^3 )   [
> 8]  1945.65216 a.u.^3 (   288.31590 Ang^3 )
> [ 9]  new unit-cell volume =   1944.65689 a.u.^3 (   288.16842 Ang^3 )   [
> 9]  1941.13802 a.u.^3 (   287.64697 Ang^3 )
> [10]  new unit-cell volume =   1940.96635 a.u.^3 (   287.62153 Ang^3 )
> [10]  1939.06064 a.u.^3 (   287.33914 Ang^3 )
> [11]  new unit-cell volume =   1939.90715 a.u.^3 (   287.46458 Ang^3 )
> [11]  1938.65781 a.u.^3 (   287.27944 Ang^3 )
> [12]  new unit-cell volume =   1939.26844 a.u.^3 (   287.36993 Ang^3 )
> [12]  1938.21336 a.u.^3 (   287.21358 Ang^3 )
> [13]  new unit-cell volume =   1937.86399 a.u.^3 (   287.16181 Ang^3 )
> [13]  1936.17781 a.u.^3 (   286.91195 Ang^3 )
> [14]  new unit-cell volume =   1936.35258 a.u.^3 (   286.93784 Ang^3 )
> [14]  1934.16215 a.u.^3 (   286.61326 Ang^3 )
> [15]  new unit-cell volume =   1934.47381 a.u.^3 (   286.65944 Ang^3 )
> [15]  1932.10493 a.u.^3 (   286.30841 Ang^3 )
> [16]  new unit-cell volume =   1932.63674 a.u.^3 (   286.38721 Ang^3 )
> [16]  1930.22378 a.u.^3 (   286.02965 Ang^3 )
> [17]  new unit-cell volume =   1930.23334 a.u.^3 (   286.03107 Ang^3 )
> [17]  1927.83544 a.u.^3 (   285.67574 Ang^3 )
> [18]  new unit-cell volume =   1926.68480 a.u.^3 (   285.50523 Ang^3 )
> [18]  1924.38618 a.u.^3 (   285.16461 Ang^3 )
> [19]  new unit-cell volume =   1922.08253 a.u.^3 (   284.82324 Ang^3 )
> [19]  1920.03850 a.u.^3 (   284.52035 Ang^3 )
> [20]  new unit-cell volume =   1918.60656 a.u.^3 (   284.30816 Ang^3 )
> [20]  1918.67621 a.u.^3 (   284.31848 Ang^3 )
> [21]  new unit-cell volume =   1917.76107 a.u.^3 (   284.18287 Ang^3 )
> [21]  1917.87993 a.u.^3 (   284.20048 Ang^3 )
> [22]  new unit-cell volume =   1917.99827 a.u.^3 (   284.21802 Ang^3 )
> [22]  1918.22644 a.u.^3 (   284.25183 Ang^3 )
> [23]  new unit-cell volume =   1917.99827 a.u.^3 (   284.21802 Ang^3 )
> [23]  1918.22644 a.u.^3 (   284.25183 Ang^3 )
> [24]  unit-cell volume          =    1917.9983 (a.u.)^3
>            [24]   =    1918.2264 (a.u.)^3
> 
> ------------------------------------------------------------
> Prof. Carlo Nervi carlo.nervi at unito.it  Tel:+39 0116707507/8
> Fax: +39 0116707855      -      Dipartimento di Chimica, via
> P. Giuria 7, 10125 Torino, Italy.    http://lem.ch.unito.it/

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   Giuseppe Mattioli                            
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10                
   I 00015 - Monterotondo Stazione (RM)          
   Tel + 39 06 90672836 - Fax +39 06 90672316    
   E-mail: <giuseppe.mattioli at ism.cnr.it>
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   ResearcherID: F-6308-2012




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