3.1.11 IBRAV=405 simple trigonal lattice(単純三方格子)

CELLDM(1) $=a$, CELLDM(4) $=\cos{\alpha} (0 < \alpha < 120^{\circ})$,
$b\equiv\sqrt{2} a \sqrt{1-\cos{\alpha}}/\sqrt{3}$, $c\equiv a \sqrt{1+2\cos{\alpha}}/\sqrt{3}$
$\Omega=a^{3}(1-\cos{\alpha})\sqrt{1+2\cos{\alpha}}=3\sqrt{3} b^2 c/2$
$({\bf a}_{1},{\bf a}_{2},{\bf a}_{3})= ({\bf x},{\bf y},{\bf z}) \left( \beg... ...{3}b}{2}\\ b & -\frac{b}{2} & -\frac{b}{2}\\ c & c & c \end{array} \right)$
$({\bf b}_{1},{\bf b}_{2},{\bf b}_{3})= \frac{2 \pi}{a} ({\bf x},{\bf y},{\bf ... ...rt{3} b \\ 2a/3b & -a/3b & -a/3b \\ a/3c & a/3c & a/3c \end{array} \right)$