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

Table 2: PW-LDA/USP MSI theoretical calculations on α-Quartz. Effect of the energycutoff and of the number of k-points for sampling the Brillouin zone. See Table 1 forother details.E c 340.(2) a 340.(4) a 340.(8) a 400. b 500. b 600. b 600. ca (Å) 4.9190 4.9077 4.9249 4.8784 4.8721 4.8759 4.8771c (Å) 5.4208 5.4081 5.4185 5.3707 5.3694 5.3710 5.3701V (Å 3 ) 113.6 112.8 113.8 110.7 110.4 110.6 110.6Si (x) 0.4766 0.4751 0.4769 0.4710 0.4709 0.4710 0.4710O (x) 0.4167 0.4165 0.4171 0.4149 0.4150 0.4151 0.4153O (y) 0.2550 0.2578 0.2545 0.2647 0.2651 0.2647 0.2647O (z) 0.1302 0.1280 0.1307 0.1222 0.1220 0.1223 0.1223Si-O (av.) 1.592 1.591 1.592 1.591 1.590 1.591 1.591Si-O-Si 147.8 147.1 148.1 145.0 144.9 145.0 145.0a FFT grid=fine, in parentheses number of k-pointsb Tol.=defaultc FFT grid=fine; k-points=4;Table 3: PW-GGA/USP MSI theoretical calculations on α-Quartz. Effect of the energycutoff and of the number of k-points for sampling the Brillouin zone. See Table 1 forother details.E c 340. a 400. b 400. 500. ba (Å) 4.9626 4.9842 4.9861 4.9821c (Å) 5.4722 5.4862 5.4664 5.4683V (Å 3 ) 116.7 118.0 117.7 117.5Si (x) 0.4879 0.4901 0.4901 0.4907O (x) 0.4198 0.4208 0.4197 0.4196O (y) 0.2339 0.2299 0.2288 0.2277O (z) 0.1477 0.1512 0.1517 0.1526Si-O (av.) 1.585 1.587 1.586 1.586Si-O-Si 152.9 153.8 153.5 153.6a k-points=8b FFT grid=default16