New ultrasoft pseudopotentials for the study of silicates. - STFC's ...

TablesTable 1: DFT first principles theoretical calculations on α-Quartz. Review of publisheddata. Structural data: unit-cell constants, volume, fractional atomic coordinates, averageSi-O bond length (in Å), Si-O-Si bond angle (in deg). Computational details: kineticenergy cut-off, pseudopotential, number of k-points.Expt. c Expt. c LDA LDA LDA LDA LDA LDA LDA LDA AE-PW-LDA AE-LDAa (Å) 4.914 4.902 4.913 4.89 4.876 4.954 4.892 4.920 4.84 4.899 4.844 4.840c (Å) 5.406 5.400 5.405 5.49 5.405 5.441 5.389 5.412 5.41 5.383 5.347 5.394V (Å 3 ) 113.1 112.5 113.0 113.7 111.3 115.6 111.7 113.5 109.8 111.9 108.6 109.4Si (x) 0.4700 0.4680 0.4638 0.469 0.4654 0.4750 0.4664 0.4695 0.460 0.4628O (x) 0.4131 0.4124 0.4081 0.418 0.4125 0.4151 0.4129 0.4147 0.409 0.4049O (y) 0.2677 0.2712 0.2758 0.274 0.2745 0.2584 0.2730 0.2670 0.280 0.2808O (z) 0.1189 0.1163 0.1215 0.118 0.1143 0.1264 0.1152 0.1199 0.108 0.1065Si-O (av.) 1.610 1.613 1.621 1.612 1.611 1.607 1.610 1.614 1.602 1.614 1.626Si-O-Si 143.5 142.4 141.8 143.8 141.8 146.3 142.2 140.2 144.1 139.2 137.5E c (eV) 870. 340. 1600. 400. 700. 544. 396.PP a,b NC(T) NC(TM) US(V) NC(T) US(V) NC(TM) NC(H) US(V)k-p. 3 6 4 2 14 6 7Ref. [11] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] dExpt. c Expt. c GGA GGA AE-PW-GGA AE-GGAa (Å) 4.914 4.902 4.97 5.027 4.990 4.958c (Å) 5.406 5.400 5.52 5.509 5.484 5.433V (Å 3 ) 113.1 112.5 118.1 120.6 118.5 115.7Si (x) 0.4700 0.4680 0.4814 0.474 0.4650O (x) 0.4131 0.4124 0.4165 0.413 0.4100O (y) 0.2677 0.2712 0.2460 0.261 0.2777O (z) 0.1189 0.1163 0.1364 0.123 0.1087Si-O (av.) 1.610 1.613 1.623 1.615 1.627 1.644Si-O-Si 143.5 142.4 145.5 149.1 144.8 139.5E c (eV) 544. 396.PP a,b NC(H) US(V)k-p. 2 14 6 7Ref. [11] [11] [18] [19] [20] da NC=Norm-Conserving, US=Ultra-Soft; b T=Teter, TM=Trouiller-Martins, V=Vanderbilt, H=Hamannc 296 K and 13 K, respectively.d Present work15