From P. Atkin’s The Elements of Physical Chemistry

Diatomic Molecules: Rotational Degrees of Freedom

Non-Linear Triatomic Molecules:

Rotational Degrees of Freedom

From P. Atkin’s The Elements of Physical Chemistry

Linear Triatomic Molecules:

Vibrational Degrees of Freedom

Symmetric and anti-symmetric stretching vibration

From P. Atkin’s The Elements of Physical Chemistry

Bending vibration

Contributes 1 kT in thermal energy