Question

1. Fluorescein isothiocyanate (FITC) is a dye commonly used in scientific research to label proteins and other molecules for visualization in experiments. FITC has an absorbed λmax​ of 516 nm. What is the ΔE between the HOMO and LUMO in eV for FITC? Enter only two digits, and do not enter units (i.e. enter 9.8)

Answer 1

Since the observed , the photon that is being released from the HOMO-LUMO transition must have an wavelength of 516 nm.

As the energy of the HOMO-LUMO must match with the energy of the photon, we can calculate the HOMO-LUMO gap by equating it with the energy of the photon.

Hence,

The energy of the photon of wavelength 516 nm is

Now we have to convert Joules into eV.

Hence,

Hence, the energy difference between HOMO and LUMO is 2.4 eV

So you should put 2.4 as your answer.