Q99 · CSIR NET Chemistry, December 2011
Paper: CSIR NET December 2011 · Subject: Physical Chemistry · Chapter: Group Theory · Topic: Character Tables · Marks: 2 · Difficulty: Hard
The character table for the $D_4$ point group is provided below:
For this point group, the correct statement among the following is:
| $\mathrm{D}_{3}$ | E | $2 \mathrm{C}_{3}$ | 3C | ||
|---|---|---|---|---|---|
| $\mathrm{A}_{1}$ | 1 | 1 | 1 | $x^{2}+y^{2} . z^{2}$ | |
| $\mathrm{A}_{2}$ | 1 | 1 | -1 | z. $\mathrm{R}_{2}$ | |
| E | 2 | -1 | 0 | $(\mathrm{x}, \mathrm{y}),\left(\mathrm{R}_{\mathrm{x}}, \mathrm{R}_{\mathrm{y}}\right)$ | ( $\left.\mathrm{x}^{2}-\mathrm{y}^{2}-\mathrm{xy}\right)$, (xz, yz) |
(a)it is possible to have a totally symmetric normal mode of vibration which is IR-active
(b)all IR-active normal modes are necessarily Raman inactive
(c)all Raman-active normal modes are necessarily IR-active
(d)it is possible to have a pair of IR-active normal modes that are degenerate.
Answer
Answer (as printed): D
Explanation
No explanation was printed for this question.
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