How Do You Calculate The Frequencies Of A Triatomic Molecule?
Vibration frequencies are necessary to understand molecular physics. Calculating these frequencies begins with a degrees of freedom (DoF) assessment. Experiments, tabulated data, and/or more extensive quantum mechanics mathematics reveal bond length, bond angle and force constant data. Molecular vibration mode equations are helpful in determining the relevant frequency values. Determine how many degrees of freedom the molecule has. A triatomic molecule has three atoms. There are 3n-5 degrees of freedom if the atoms are linear. If the three atoms are not in a line, as with H2O, then degrees of freedom = 3n-6. Variable “n” refers to how many atoms are in the molecule. Since we know there are three atoms, we have 3(3)-5 = 4 degrees of freedom for linear triatomic molecules and 3(3)-6 = 3 degrees of freedom for non-linear molecules. Measure or research molecular bond lengths. A triatomic molecule has two bonds (b1, b2). For each of those bonds, there are two relevant measurements. The meas
