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Tables of descent in symmetry
These tables show the correlations between the irreps of an overgroup with those of some of its subgroups.
$\newcommand{\mirror}[1]{\sigma_\mathrm{#1}}
\newcommand{\rowthree}[3]{\mathrm{#1}&\mathrm{#2}&\mathrm{#3}\\}
\newcommand{\rowfour}[4]{\mathrm{#1}&\mathrm{#2}&\mathrm{#3}&\mathrm{#4}\\}
\newcommand{\rowfive}[5]{\mathrm{#1}&\mathrm{#2}&\mathrm{#3}&\mathrm{#4}&\mathrm{#5}\\}
\newcommand{\rowsix}[6]{\mathrm{#1}&\mathrm{#2}&\mathrm{#3}&\mathrm{#4}&\mathrm{#5}&\mathrm{#6}\\}
\newcommand{\rowseven}[7]{\mathrm{#1}&\mathrm{#2}&\mathrm{#3}&\mathrm{#4}&\mathrm{#5}&\mathrm{#6}&\mathrm{#7}\\}
\newcommand{\roweight}[8]{\mathrm{#1}&\mathrm{#2}&\mathrm{#3}&\mathrm{#4}&\mathrm{#5}&\mathrm{#6}&\mathrm{#7}&\mathrm{#8}\\}$
- A sub-heading $A$ identifies which symmetry element(s) in the overgroup is/are preserved as symmetry element(s) in the subgroup.
- A sub-heading $A \to B$ indicates that symmetry element $A$ in the overgroup becomes symmetry element $B$ in the subgroup.
- In the subgroup $C_\mathrm{s}$ there is only one mirror plane, and therefore no ambiguity. However, in $C_\mathrm{2v}$ there are two mirror planes. Which mirror plane becomes $\mirror{v}$, and which becomes $\mirror{v}'$, cannot be uniquely defined and must be set by a convention. This convention is either indicated clearly, or omitted if it does not affect the resulting irreps (because they appear together as a sum $\mathrm{B_1 + B_2}$). In the latter case, this is indicated by a dagger symbol, $^\dagger$. Similar ambiguity is present in the three degenerate rotation axes of $D_2$ and $D_\mathrm{2h}$.
Tables for any omitted overgroups, as well as correlations for most omitted subgroups (listed below each table), can be found in Appendix X-8 of Molecular Vibrations: The Theory of Infrared and Raman Vibrational Spectra by Wilson, Decius, and Cross. The tables presented here have been checked against this source. If I have time, I may add more tables from there.
$$\begin{array}{ccc}
\begin{array}{c|ccc} \hline
C_\mathrm{2v} & C_2 & C_\mathrm{s} & C_\mathrm{s} \\
& & \sigma(xz) & \sigma(yz) \\ \hline
\rowfour{A_1}{A}{A' }{A' }
\rowfour{A_2}{A}{A''}{A''}
\rowfour{B_1}{B}{A' }{A''}
\rowfour{B_2}{B}{A''}{A' } \hline
\end{array} & \quad &
\begin{array}{c|ccc} \hline
C_\mathrm{3v} & C_3 & C_\mathrm{s} \\ \hline
\rowthree{A_1}{A}{A' }
\rowthree{A_2}{A}{A'' }
\rowthree{E }{E}{A'+A''} \hline
\end{array}
\end{array}$$
$\,$
$$\begin{array}{c|cc} \hline
C_\mathrm{4v} & C_\mathrm{2v} & C_\mathrm{2v} \\
& \mirror{v} & \mirror{d} \\ \hline
\rowthree{A_1}{A_1 }{A_1 }
\rowthree{A_2}{A_2 }{A_2 }
\rowthree{B_1}{A_1 }{A_2 }
\rowthree{B_2}{A_2 }{A_1 }
\rowthree{E }{B_1+B_2}{B_1+B_2}\hline
\end{array} \\
\text{also: }C_4, C_2, C_\mathrm{s}$$
$\,$
$$\begin{array}{c|cccccc} \hline
D_\mathrm{2h} & D_2 & C_\mathrm{2v} & C_\mathrm{2v} & C_\mathrm{2v} & C_\mathrm{2h} & C_\mathrm{2h} & C_\mathrm{2h} \\
& & C_2(z) & C_2(y) & C_2(x) & C_2(z) & C_2(y) & C_2(x) \\ \hline
\roweight{A_g }{A }{A_1}{A_1}{A_1}{A_g}{A_g}{A_g}
\roweight{B_{1g}}{B_1}{A_2}{B_2}{B_1}{A_g}{B_g}{B_g}
\roweight{B_{2g}}{B_2}{B_1}{A_2}{B_2}{B_g}{A_g}{B_g}
\roweight{B_{3g}}{B_3}{B_2}{B_1}{A_2}{B_g}{B_g}{A_g}
\roweight{A_u }{A }{A_2}{A_2}{A_2}{A_u}{A_u}{A_u}
\roweight{B_{1u}}{B_1}{A_1}{B_1}{B_2}{A_u}{B_u}{B_u}
\roweight{B_{2u}}{B_2}{B_2}{A_1}{B_1}{B_u}{A_u}{B_u}
\roweight{B_{3u}}{B_3}{B_1}{B_2}{A_1}{B_u}{B_u}{A_u} \hline
\end{array}$$
$$\begin{array}{c|cccccc} \hline
D_\mathrm{2h} & C_2 & C_2 & C_2 & C_\mathrm{s} & C_\mathrm{s} & C_\mathrm{s} \\
\text{cont.} & C_2(z) & C_2(y) & C_2(x) & \mirror{xy} & \mirror{zx} & \mirror{yz} \\ \hline
\rowseven{A_g }{A}{A}{A}{A' }{A' }{A' }
\rowseven{B_{1g}}{A}{B}{B}{A' }{A''}{A''}
\rowseven{B_{2g}}{B}{A}{B}{A''}{A' }{A''}
\rowseven{B_{3g}}{B}{B}{A}{A''}{A''}{A' }
\rowseven{A_u }{A}{A}{A}{A''}{A''}{A''}
\rowseven{B_{1u}}{A}{B}{B}{A''}{A' }{A' }
\rowseven{B_{2u}}{B}{A}{B}{A' }{A''}{A' }
\rowseven{B_{3u}}{B}{B}{A}{A' }{A' }{A''} \hline
\end{array}$$
$\,$
$$\begin{array}{c|ccccc} \hline
D_\mathrm{3h} & C_\mathrm{3h} & C_\mathrm{3v} & C_\mathrm{2v} & C_\mathrm{s} & C_\mathrm{s} \\
& & & \mirror{h}\to\mirror{v}(yz) & \mirror{h} & \mirror{v} \\ \hline
\rowsix{A_1' }{A' }{A_1}{A_1 }{A' }{A' }
\rowsix{A_2' }{A' }{A_2}{B_2 }{A' }{A'' }
\rowsix{E' }{E' }{E }{A_1+B_2}{2A' }{A'+A''}
\rowsix{A_1''}{A''}{A_2}{A_2 }{A'' }{A'' }
\rowsix{A_2''}{A''}{A_1}{B_1 }{A'' }{A' }
\rowsix{E'' }{E''}{E }{A_2+B_1}{2A''}{A'+A''} \hline
\end{array} \\
\text{also: }D_3, C_3, C_2$$
$\,$
$$\begin{array}{c|cccccc} \hline
D_\mathrm{4h} & D_\mathrm{2d} & D_\mathrm{2d} & D_\mathrm{2h} & D_\mathrm{2h} & D_\mathrm{2} & D_\mathrm{2} \\
& C_2' \to C_2' & C_2'' \to C_2' & C_2' & C_2'' & C_2' & C_2'' \\ \hline
\rowseven{A_{1g}}{A_1}{A_1}{A_g }{A_g }{A }{A }
\rowseven{A_{2g}}{A_2}{A_2}{B_{1g} }{B_{1g} }{B_1 }{B_1 }
\rowseven{B_{1g}}{B_1}{B_2}{A_g }{B_{1g} }{A }{B_1 }
\rowseven{B_{2g}}{B_2}{B_1}{B_{1g} }{A_g }{B_1 }{A }
\rowseven{E_g }{E }{E }{B_{2g}+B_{3g}}{B_{2g}+B_{3g}}{B_2+B_3}{B_2+B_3}
\rowseven{A_{1u}}{B_1}{B_1}{A_u }{A_u }{A }{A }
\rowseven{A_{2u}}{B_2}{B_2}{B_{1u} }{B_{1u} }{B_1 }{B_1 }
\rowseven{B_{1u}}{A_1}{A_2}{A_u }{B_{1u} }{A }{B_1 }
\rowseven{B_{2u}}{A_2}{A_1}{B_{1u} }{A_u }{B_1 }{A }
\rowseven{E_u }{E }{E }{B_{2u}+B_{3u}}{B_{2u}+B_{3u}}{B_2+B_3}{B_2+B_3} \hline
\end{array}$$
$$\begin{array}{c|cccc} \hline
D_\mathrm{4h} & C_\mathrm{4h} & C_\mathrm{4v} & C_\mathrm{2v}{}^\dagger & C_\mathrm{2v}{}^\dagger \\
\text{(cont.)} & & & C_2,\mirror{v} & C_2,\mirror{d} \\ \hline
\rowfive{A_{1g}}{A_g}{A_1}{A_1 }{A_1 }
\rowfive{A_{2g}}{A_g}{A_2}{A_2 }{A_2 }
\rowfive{B_{1g}}{B_g}{B_1}{A_1 }{A_2 }
\rowfive{B_{2g}}{B_g}{B_2}{A_2 }{A_1 }
\rowfive{E_g }{E_g}{E }{B_1+B_2}{B_1+B_2}
\rowfive{A_{1u}}{A_u}{A_2}{A_2 }{A_2 }
\rowfive{A_{2u}}{A_u}{A_1}{A_1 }{A_1 }
\rowfive{B_{1u}}{B_u}{B_2}{A_2 }{A_1 }
\rowfive{B_{2u}}{B_u}{B_1}{A_1 }{A_2 }
\rowfive{E_u }{E_u}{E }{B_1+B_2}{B_1+B_2} \hline
\end{array} \\
\text{also: }D_4, C_4, S_4, C_\mathrm{2v}(C_2'), C_\mathrm{2v}(C_2''), C_\mathrm{2h}(C_2), C_\mathrm{2h}(C_2'), C_\mathrm{2h}(C_2''), C_2(C_2), C_2(C_2'), C_2(C_2''), C_\mathrm{s}(\mirror{h}), C_\mathrm{s}(\mirror{v}), C_\mathrm{s}(\mirror{d}), C_\mathrm{i}$$
$\,$
$$\begin{array}{c|cccccc} \hline
D_\mathrm{6h} & D_\mathrm{3d} & D_\mathrm{3d} & D_\mathrm{2h} & C_\mathrm{6v} & C_\mathrm{3v} & C_\mathrm{3v} \\
& C_2'' & C_2' & \mirror{h}\to\sigma(xy) & & \mirror{v} & \mirror{d} \\
& & & \mirror{v}\to\sigma(yz) & & & \\ \hline
\rowseven{A_{1g}}{A_{1g}}{A_{1g}}{A_g }{A_1}{A_1}{A_1}
\rowseven{A_{2g}}{A_{2g}}{A_{2g}}{B_{1g} }{A_2}{A_2}{A_2}
\rowseven{B_{1g}}{A_{2g}}{A_{1g}}{B_{2g} }{B_2}{A_2}{A_1}
\rowseven{B_{2g}}{A_{1g}}{A_{2g}}{B_{3g} }{B_1}{A_1}{A_2}
\rowseven{E_{1g}}{E_{g} }{E_{g} }{B_{2g}+B_{3g}}{E_1}{E }{E }
\rowseven{E_{2g}}{E_{g} }{E_{g} }{A_g+B_{1g} }{E_2}{E }{E }
\rowseven{A_{1u}}{A_{1u}}{A_{1u}}{A_u }{A_2}{A_2}{A_2}
\rowseven{A_{2u}}{A_{2u}}{A_{2u}}{B_{1u} }{A_1}{A_1}{A_1}
\rowseven{B_{1u}}{A_{2u}}{A_{1u}}{B_{2u} }{B_1}{A_1}{A_2}
\rowseven{B_{2u}}{A_{1u}}{A_{2u}}{B_{3u} }{B_2}{A_2}{A_1}
\rowseven{E_{1u}}{E_{u} }{E_{u} }{B_{2u}+B_{3u}}{E_1}{E }{E }
\rowseven{E_{2u}}{E_{u} }{E_{u} }{A_u+B_{1u} }{E_2}{E }{E } \hline
\end{array}$$
$$\begin{array}{c|ccccc} \hline
D_\mathrm{6h} & C_\mathrm{2v} & C_\mathrm{2v} & C_\mathrm{2h} & C_\mathrm{2h} & C_\mathrm{2h} \\
\text{(cont.)} & C_2' & C_2'' & C_2 & C_2' & C_2'' \\
& \mirror{h}\to\sigma(xz) & \mirror{h}\to\sigma(xz) & & & \\ \hline
\rowsix{A_{1g}}{A_1 }{A_1 }{A_g }{A_g }{A_g }
\rowsix{A_{2g}}{B_1 }{B_1 }{A_g }{B_g }{B_g }
\rowsix{B_{1g}}{A_2 }{B_2 }{B_g }{A_g }{B_g }
\rowsix{B_{2g}}{B_2 }{A_2 }{B_g }{B_g }{A_g }
\rowsix{E_{1g}}{A_2+B_2}{A_2+B_2}{2B_g}{A_g+B_g}{A_g+B_g}
\rowsix{E_{2g}}{A_1+B_1}{A_1+B_1}{2A_g}{A_g+B_g}{A_g+B_g}
\rowsix{A_{1u}}{A_2 }{A_2 }{A_u }{A_u }{A_u }
\rowsix{A_{2u}}{B_2 }{B_2 }{A_u }{B_u }{B_u }
\rowsix{B_{1u}}{A_1 }{B_1 }{B_u }{A_u }{B_u }
\rowsix{B_{2u}}{B_1 }{A_1 }{B_u }{B_u }{A_u }
\rowsix{E_{1u}}{A_1+B_1}{A_1+B_1}{2B_u}{A_u+B_u}{A_u+B_u}
\rowsix{E_{2u}}{A_2+B_2}{A_2+B_2}{2A_u}{A_u+B_u}{A_u+B_u} \hline
\end{array} \\
\text{also: }D_6, D_\mathrm{3h}(C_2'), D_\mathrm{3h}(C_2''), C_\mathrm{6h}, C_6, C_\mathrm{3h}, D_3(C_2'), D_3(C_2''), S_6, D_2, C_3, C_2(C_2), C_2(C_2'), C_2(C_2''), C_\mathrm{s}(\mirror{h}), C_\mathrm{s}(\mirror{d}), C_\mathrm{s}(\mirror{v}), C_\mathrm{i} $$
$\,$
$$\begin{array}{c|cccc} \hline
T_\mathrm{d} & T & D_\mathrm{2d} & C_\mathrm{3v} & C_\mathrm{2v}{}^\dagger \\ \hline
\rowfive{A_1}{A}{A_1 }{A_1 }{A_1 }
\rowfive{A_2}{A}{B_1 }{A_2 }{A_2 }
\rowfive{E }{E}{A_1+B_1}{E }{A_1+A_2 }
\rowfive{T_1}{T}{A_2+E }{A_2+E}{A_2+B_1+B_2}
\rowfive{T_2}{T}{B_2+E }{A_1+E}{A_1+B_1+B_2} \hline
\end{array} \\
\text{also: }S_4, D_2, C_3, C_2, C_\mathrm{s}$$
$\,$
$$\begin{array}{c|ccccccccc} \hline
O_\mathrm{h} & O & T_\mathrm{d} & T_\mathrm{h} & D_\mathrm{4h} & D_\mathrm{2d} & C_\mathrm{4v} & C_\mathrm{2v}{}^\dagger \\
& & & & & & & C_2,\mirror{h},\mirror{d} \\ \hline
\roweight{A_{1g}}{A_1}{A_1}{A_g}{A_{1g} }{A_1 }{A_1 }{A_1 }
\roweight{A_{2g}}{A_2}{A_2}{A_g}{B_{1g} }{B_1 }{B_1 }{A_2 }
\roweight{E_g }{E }{E }{E_g}{A_{1g}+B_{1g}}{A_1+B_1}{A_1+B_1}{A_1+A_2 }
\roweight{T_{1g}}{T_1}{T_1}{T_g}{A_{2g}+E_g }{A_2+E }{A_2+E }{A_2+B_1+B_2}
\roweight{T_{2g}}{T_2}{T_2}{T_g}{B_{2g}+E_g }{B_2+E }{B_2+E }{A_1+B_1+B_2}
\roweight{A_{1u}}{A_1}{A_2}{A_u}{A_{1u} }{B_1 }{A_2 }{A_2 }
\roweight{A_{2u}}{A_2}{A_1}{A_u}{B_{1u} }{A_1 }{B_2 }{A_1 }
\roweight{E_u }{E }{E }{E_u}{A_{1u}+B_{1u}}{A_1+B_1}{A_2+B_2}{A_1+A_2 }
\roweight{T_{1u}}{T_1}{T_2}{T_u}{A_{2u}+E_u }{B_2+E }{A_1+E }{A_1+B_1+B_2}
\roweight{T_{2u}}{T_2}{T_1}{T_u}{B_{2u}+E_u }{A_2+E }{B_1+E }{A_2+B_1+B_2} \hline
\end{array}$$
$$\begin{array}{c|ccc} \hline
O_\mathrm{h} & D_\mathrm{3d} & D_3 & C_\mathrm{2h} \\
\text{(cont.)} & & & C_2 \\ \hline
\rowfour{A_{1g}}{A_{1g} }{A_1 }{A_g }
\rowfour{A_{2g}}{A_{2g} }{A_2 }{B_g }
\rowfour{E_g }{E_g }{E }{A_g+B_g }
\rowfour{T_{1g}}{A_{2g}+E_g}{A_2+E}{A_g+2B_g}
\rowfour{T_{2g}}{A_{1g}+E_g}{A_1+E}{2A_g+B_g}
\rowfour{A_{1u}}{A_{1u} }{A_1 }{A_u }
\rowfour{A_{2u}}{A_{2u} }{A_2 }{B_u }
\rowfour{E_u }{E_u }{E }{A_u+B_u }
\rowfour{T_{1u}}{A_{2u}+E_u}{A_2+E}{A_u+2B_u}
\rowfour{T_{2u}}{A_{1u}+E_u}{A_1+E}{2A_u+B_u} \hline
\end{array} \\
\text{Note that }C_2' \equiv C_4^2\text{ and }C_2 \not\equiv C_4^2\text{.} \\
\text{also: }T, D_4, C_\mathrm{4h}, D_\mathrm{2h}(3C_2), D_\mathrm{2h}(3C_2'), C_\mathrm{3v}, S_6, C_4, S_4, C_\mathrm{2v}(C_2',2\mirror{h}), C_\mathrm{2v}(C_2',\mirror{h},\mirror{d}), D_2(3C_2), D_2(3C_2'), C_\mathrm{2h}(C_2'), C_3, C_2(C_2), C_2(C_2'), S_2, C_\mathrm{s}$$
$\,$
$$\begin{array}{c|ccc} \hline
\mathrm{R_3} & O & D_4 & D_3 \\ \hline
\rowfour{S}{A_1 }{A_1 }{A_1 }
\rowfour{P}{T_1 }{A_2+E }{A_2+E }
\rowfour{D}{E+T_2 }{A_1+B_1+B_2+E }{A_1+2E }
\rowfour{F}{A_2+T_1+T_2 }{A_2+B_1+B_2+2E }{A_1+2A_1+2E}
\rowfour{G}{A_1+E+T_1+T_2}{2A_1+A_2+B_1+B_2+2E}{2A_1+A_2+3E}
\rowfour{H}{E+2T_1+2T_2 }{A_1+2A_2+B_1+B_2+3E}{A_1+2A_1+4E} \hline
\end{array}$$
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