I'm reading this paper, which states that the chemical potential $\mu$ is determined by the steady-state balance of up and down transitions in a fluorescent molecule. I am happy with this interpretation. But what I don't know how to verify is the next statement:
"For a high-quantum-efficiency fluorescent molecule illuminated at the earth surface, $\mu$ is usually $0.6$ or $0.7$ times $h\nu$ at the centre of the absorption band".
How would I show that $\mu$ is usually $0.6$ or $0.7$ times $h\nu$ at the centre of the absorption band?