(a)
Interpretation:
The number of IR-active vibrations for
Concept introduction:
The complex vibrations exhibit by the polyatomic molecule is known as normal modes of vibrations. The vibrational modes of a molecule are IR or Raman active. If a molecule has centre of symmetry, then the modes which are IR-active will be Raman inactive and the modes that are IR-inactive will be Raman active. The total number of vibrational degrees of freedom for nonlinear molecule is represented by
(b)
Interpretation:
The number of IR-active vibrations for
Concept introduction:
The complex vibrations exhibit by the polyatomic molecule is known as normal modes of vibrations. The vibrational modes of a molecule are IR or Raman active. If a molecule has centre of symmetry, then the modes which are IR-active will be Raman inactive and the modes that are IR-inactive will be Raman active. The total number of vibrational degrees of freedom for nonlinear molecule is represented by
(c)
Interpretation:
The number of IR-active vibrations for
Concept introduction:
The complex vibrations exhibit by the polyatomic molecule is known as normal modes of vibrations. The vibrational modes of a molecule are IR or Raman active. If a molecule has centre of symmetry, then the modes which are IR-active will be Raman inactive and the modes that are IR-inactive will be Raman active. The total number of vibrational degrees of freedom for nonlinear molecule is represented by
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Chapter 14 Solutions
Physical Chemistry
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- Consider the three following molecules and answer the questions below.HC≡CHH2C=CH2H3C-CH3 (3 conformers with different symmetry)(a) For each molecule, including all conformers as indicated, draw the molecule, assign it toits point group, and draw on the diagram the symmetry elements that were used to makethe assignment. State in each case whether or not the species is dipolar and/or chiral.(b) If one hydrogen atom in each molecule is substituted by a chlorine atom, sketch the newmolecules and assign them to their point group. For this set of mono-chloro compounds: state the most common point group state how many are chiral state how many are dipolar state which molecule/conformer has the highest symmetry point group state which molecule/conformer has the lowest symmetry point group identify which of these molecules/conformers have three different H atomenvironments(c) For the dichlorinated versions of the molecules/conformers considered in part (a): state the most common point…arrow_forward(c) Determine the results of the following multiplications of symmetry operations for the anthracene molecule (chemical structure shown below, C2 represents the main axis). [5 (i) C2. Oh (ii) i C₂ (iii) E-ov O 500arrow_forwardConsider the molecule CH3Cl. (a) To what point group does the molecule belong? (b) How many normal modes of vibration does the molecule have? (c) What are the symmetry species of the normal modes of vibration of this molecule? (d) Which of the vibrational modes of this molecule are infrared active? (e) Which of the vibrational modes of this molecule are Raman active?arrow_forward
- Consider HCN, which has three features in its IR spectrum: 946, 2380, and -1 3386 cm¹. (a) Sketch the motions of each normal mode and denote any degeneracies. (b) Assign each feature in the IR spectrum to a normal mode of the molecule. (c) Determine the zero-point energy of HCN.arrow_forwardDraw the shape of the [XeF5]- ion and answer the questions below: (i) List the symmetry elements and the symmetry operations of the [XeF5]- ion. (ii) What is the point group of the [XeF5]- ion? What is the order of the point group of the [XeF5]- ion? (iii) Using the [XeF5]- as an example, show that Cnn ≡ E.arrow_forward(b) The lowest frequency rotational transition of ²H³³C1 occurs at 10.92 cm1. Determine (i) The rotational constant, B, in Hz (ii) The bond lengtharrow_forward
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