Question

If s FTIR can produce a resolution down to 0.0125 cm-1. How far does the mirror in the interferometer travel in each cycly for this resolution?

Answer 1

Solution:

In an FTIR spectroscopy, the relation between the spectral line spacing (or resolution) and the optical retardation (or the distance traveled by moving mirror) is given by

R = 1/d

Where,

R = Resolution in wavenumber

d = Distance traveled by mirror in cm

Now, as given in the problem,

Resolution (R) = 0.0125 /cm

Therefore, from above equation,

d = 1/0.0125 cm

or, d = 80 cm

Thus, the mirror in the interferometer must travel a distance of 80 cm to achieve the resolution of 0.0125 cm^-1