Question

11. The molecule methane, representation of the four C-H bonds is formed T2 irreducible representation. How predict and Raman active C-H stretching vibratio 33 to the Ta point group (found below). The reducible our C-H bonds is formed from one A irreducible representation and one presentation. How many infrared active C-H stretching vibrations would you Raman active C-H stretching vibrations would you predict for CHA? (4 points) Character table for T, point group Esc, 3c, 6s, 600 A1 1 1 1 1 rotations quadratic x²+z²+z² E2- 12 0 0 (22²-x²7², x²-y) 13 0-1 1-1 R, R, R) 12 3 0 -1 -1 i (x, y, z) (xy, xz, yz) 12. The hydronium ion, H30", belongs to the Czy point group. Given the Czy character table found below and the reducible representation of the combination of the hydrogen is orbitals, generate an appropriate molecular orbital energy level diagram for this ion. How many different energy levels do the valence electrons in the hydronium ion occupy? (8 points) Character table for C3 point group linear, E 2C3 (2) 30 quadratic rotations A1 1 1 1 2 x2+y?,z2 A21/1 - R₂ E 2-1 0 (x,y) (Rx, Ry) (x2-y?, xy) (x2, yz) 3 0 1

Answer 1

11. CHA & Ta point group Character table is given in the question. The function x, y, z in the character table represent the IRS (Irreducible representation or symmetry specles, to which the corresponding componants Mx, My and ux of the dipole moment belong. Infrared transitions originate from the dipole moment operator whose symmetry is same as the vector along xy and Z axis. Again, Raman spectral absorption does not depend on the dipole moment operator, but on the polarizability Visa operator (&), which contains binary and quadratic cartesian functions such as x², y 2 x², xy, yz, ZX and their combinations Among the Ag and To Stretching mode of vibration Al is only Raman active and to is Raman active as well as IR active So I IR active C-H stretching vibration is present, which is to And, 2 Raman active C-H stretching vibration is present, which are Al and To.