Chapter 20: Q29P (page 527)

Explain why the transmission spectrum is calculated from the quotient (sample transform) M(background transform) instead of the difference (sample transform) - (background transform).

Short Answer

Expert verified

The transmittance spectrum was explained using the quotient (sample transform / background transform) rather than the difference (sample transform) (background transform).

Step by step solution

Definition of transmission spectrum

Because more light is passed through the sample, the maximum intensities of a transmission spectrum will be at wavelengths where the absorption is weakest.
The maximum intensities in an absorption spectrum occur at wavelengths where the absorption is strongest.

Determine the transmission spectrum is calculated from the quotient (sample transform) M (background transform) instead of the difference (sample transform) - (background transform).

The transmittance spectrum must be stated using the quotient (sample transform / background transform) rather than the difference (sample transform) (background transform).
The background correction is a measurement of the sample's transmittance by comparing it to the backdrop's transmittance, which is utilised in the background correction.
The background transform observes the incident irradiance Po, while the sample transform observes the transmitted irradiance P.
As a result, the transmittance is, $\frac{P}{P_{o}}$ not $P ‐ P_{o}$
The transmittance spectrum was explained using the quotient (sample transform / background transform) rather than the difference (sample transform) (background transform).