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## Point Raman Correlation

This program calculates the correlation relations between a group-subgroup pair and classified them into IR, Raman and Hyper-Raman active. Using this program one can study the IR, Raman and Hyper-Raman behaviour for point groups group-subgroup pairs. One can have:
• Active modes (one dimensional) in the group which remains active in the subgroup.
• Degenerate active modes (dimension > 1) in the group which splits (more than one) into active in the subgroup.
• Non-active modes in the group which becomes active in the subgroup.

### Input of the program

One have to select a point group from the initial table:

Then one have to select the subgroup(s) of the point group:

And the program will show which are the relations and the behaviour of the modes.

### Output of the program

Once the group and the subgroup(s) has(have) been selected the program gives the following table withe the relation and the behaviour of the modes:

 Group-subgroup pair C4h(4/m) > C2h(2/m) we have: The Raman and Hyper-Raman modes behaviour for the goup-subgroup pair is the same. There is a IR mode Bu which is IR non-active in the group but it is active in the subgroup. Group-subgroup pair C4h(4/m) > C2(2) we have: Ag, Bg, 2Eg and 1Eu modes which are not IR active in the group are active in the subgroup. Au, Bu, 1Eu and 1Eu which are not IR active modes in the group are active in the subgroup. Ag, Bg, 2Eg and 1Eu modes are Hyper-Raman active in the subgroup but they are not Hyper-Raman active in the group. Au, Bu, 1Eu and 1Eu modes are Raman active in the subgroup but they are not Raman active in the group. Group-subgroup pair C2h(2/m) > C2(2) we have: Ag and Bg modes which are not IR active in the group are active in the subgroup. Ag and Bg non Hyper-Raman active modes in the group are active in the subgroup. Au and Bu non Raman active modes in the group are active in the subgroup.