Question

Calculate the various degrees of freedom for the following molecules (for each translational, rotational and vibrational energy): (a) Xe, (b) HCl, (c) CO2, (d) CH4, (e) a polycyclic aromatic hydrocarbon (PAH

Answer 1

Hi,

first i will explain how to calculate the various degress of freedom for different types of molecules.Look at the table given below:

	Degrees of Freedom
	Translational	Rotational	Vibrational
Atoms	3	0	0
Linear Molecules	3	2	3N-5
Non-linear Molecules	3	3	3N-6

Where, N is number of atoms

For the current group of molecules, following are the degree of freedom based on above table

Molecules	Degrees of Freedom
	Translational	Rotational	Vibrational	Total
Xe	3	0	0	3
HCl	3	2	1	6
C02	3	2	4	9
CH4	3	3	9	15
PAH	3	3	294	300

HCl and C0₂ are linear molecules; while, CH4 & PAH are nonlinear molecules

hope this solves your problem