The mass to use in the expression for the vibrational frequency of a diatomic molecule is the effective mass μ= (mamb)(ma+mb) The following data on the infrared absorption of wave numbers(in cm-1):
HI - 2310
HBr - 2650
CO - 2170
HCl - 2990
NO - 1940
Determine the force constants of the bonds & arrange in order of increasing stiffness.