How to get real irreducible matrix representations from the complex irreducible matrix representations?

150 Views Asked by At

I'm trying to get real symmetry adapted orbitals for molecules with icosahedric symmetry (point groups $I$ and $I_h$) using the complete projector operator (truly projector if i=j): \begin{equation} \hat{P}_{ij}^{ \Gamma_\ell} =\frac{d_\ell}{h} \sum_{R}^h R_{ij}^{\ell } \hat{R} \end{equation} Here $R_{ij}^{\ell }$ points the element located in row $i$ and column $j$ of the irreducible matrix representation $\mathbf{R}^\ell$ corresponding to the irreducible representation labeled $\Gamma_\ell$ for the symmetry operator $\hat{R}$. $d_\ell$ is the dimension of $\mathbf{R}^\ell$ and $h$ is the group order. So I require the complete matrix representations and not only the characters. In page 655 of the officially free book Point-Group Theory Tables. Altmann and Herzig. 2nd Ed. 2011, there are tabulated generators of the irreducible (complex) matrix representations of these groups. Here arises the question: How to obtain the corresponding real (and orthogonal) irreducible matrices from the complex ones?.

Thanks in advance. Whatever kind of help is welcome. Greetings.