Orienting a Monoclinic Crystal
Posted: Thu Apr 23, 2020 2:40 pm
In the documentation for orienting monoclinic crystals in the lab frame, it says, "For short Hermann-Mauguin symbols (like P2, Cm, P21/m, etc), yC is along the unique axis...In all cases, the other two axes are arbitrary."
Why are the other two axes arbitrary if I need to align the xC, yC, and zC with xL, yL, and zL? Don't I need to know where the other two crystal axes are?
For example, I want to simulate a single spectrum where my crystal b-axis (yC) is along yL, and the crystal c-axis (13 degrees below zC/c*) is along zL. If I assume that my a-axis/xC is aligned with xL, then my Euler angles would be [0 .226 0]. However, I can't assume xC is aligned with xL due to the documentation saying that xC and zC are arbitrary.
I could be overcomplicating things, but I'd like to know exactly what picture EasySpin is working with on each individual spectrum. Any advice?
Why are the other two axes arbitrary if I need to align the xC, yC, and zC with xL, yL, and zL? Don't I need to know where the other two crystal axes are?
For example, I want to simulate a single spectrum where my crystal b-axis (yC) is along yL, and the crystal c-axis (13 degrees below zC/c*) is along zL. If I assume that my a-axis/xC is aligned with xL, then my Euler angles would be [0 .226 0]. However, I can't assume xC is aligned with xL due to the documentation saying that xC and zC are arbitrary.
I could be overcomplicating things, but I'd like to know exactly what picture EasySpin is working with on each individual spectrum. Any advice?