Problem 2 The lowest vibrational transition (from the ground vibrational state to the first excited vibrational state) of a series of hydrogen halides is measured spectroscopically, and the data is given below in wavenumbers. The mass of H is 1.0078250 amu. The mass of D = 2H = 2.014102 amu. The mass of "'F is 18.99840 amu. The mass of "Cl is 34.96885 amu. The mass of Br is 80.91629 amu. The mass of 27I is 126.90447 amu. H19F 4141.3 cm-1 H35 C1 2989.74 cm-1 H81Br 2649.72 cm H1271 2309.53 cm-1 a) Calculate the bond force constant in the harmonic approximation for these molecules. Interpret the observed trend physically. b) Predict the corresponding wavenumbers for the deuterated compounds, assuming the force constant does not change