You searched for: “visible absorption spectrophotometry
visible absorption spectrophotometry (s) (noun), visible absorption spectrophotometries (pl)
The photometric measurement of the wavelengths of observable radiation taken in by a sample and which correspond to electron transitions from the ground state to an excited state: Professor Jess Monroe developed a new visible absorption spectrophotometry device that enhanced the scientific studies in his university classes.

In the teacher's advanced physics program, his students studied the visible absorptions spectrophotometries of light energy.