3.1.18 IBRAV=11 base-centered orthorhombic(C)(底心斜方格子(C))

CELLDM(1) $=a$, CELLDM(2) $=b/a$, CELLDM(3) $=c/a$, $\Omega=abc/2$
$({\bf a}_{1},{\bf a}_{2},{\bf a}_{3})= ({\bf x},{\bf y},{\bf z}) \left( \beg... ...{2} & 0 \\ \frac{b}{2} & \frac{b}{2} & 0 \\ 0 & 0 & c \end{array} \right)$
$({\bf b}_{1},{\bf b}_{2},{\bf b}_{3})= \frac{2 \pi}{a} ({\bf x},{\bf y},{\bf ... ...rray}{ccc} 1 & -1 & 0 \\ a/b & a/b& 0 \\ 0 & 0 & a/c \end{array} \right)$