Question

Q9. How many fundamental modes of vibration are possible for Hcl ?
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Answer 1

Answer:

The first three modes (T 1u ) in descending order of normal frequencies are the translational modes of the center of mass of the HCl molecule. The next normal mode (A g ) corresponds to the totally symmetric breathing of the cage

Answer 2

The fundamental modes of vibration which are possible for HCl are three.

Explanation:

• The basic mode, fundamental mode or first harmonic mode, is the simplest normal mode where the string vibrates in a single loop.
• This first mode is denoted by n = 1.
• The second harmonic is known second mode (n = 2), which involves the string vibrating in two loops.
• n vibrating loops make up the nth harmonic.
• The first three modes in  normal frequencies  order which is in decreasing order are the translational modes of the HCl molecule.
• The next normal mode (Ag ) is representing the totally symmetric breathing of the cage.
• The next quintet (Hg ) is the symmetric stretch of the cage.