I read this in one of my textbooks that stated
Linear Triatomic Gas Molecules like CO2, HCN, CS2 in which all the atoms are linear, the total number of degrees of freedom are
Nf = NT + NR + NV where NT, NR, NV are the translational freedom, rotational freedom and vibrational freedom/s respectively.
Is this correct ? If yes then why do Linear Triatomic Gas Molecules have 7 degrees of freedom, If no then what will be the correct degree/s of freedom and why ?