A new method for calculating the CO-factored force constants of pentacarbonyliron

Using an analytical approach we were able to obtain a valid solution to the CO-factored force field of Fe(CO)5.The solution led to the relations which allow direct calculation of the CO-factored force constants from CO stretching frequencies of the all-12C16O molecule. The force constants calculated from these relations were used to estimate CO stretching frequencies of 13C16O-substituted species of Fe(CO)5. The results were found to be in very close agreement with those obtained from isotopic spectra.