Question

Consider the following statements regarding the processes of fluorescence and phosphorescence. Determine whether each statement is true for fluorescence only, true for phosphorescence only, true for both processes, or true for neither process.

a) Vibrational relaxation is a radiative process.

b) Photon absorption usually occurs when a molecule is in an excited singlet electronic state.

c) The time delay between absorbed and emitted photons can be as short as a nanosecond.

d) Energy of absorbed photon equals energy of emitted photon.

Answer 1

False for both process :

d) Energy of absorbed photon equals energy of emitted photon.

Emitted photon has lesser energy compared with Absorbed photon in both processes

a) Vibrational relaxation is a radiative process.

It is a non radiative process

True for Flouroscene only :

c) The time delay between absorbed and emitted photons can be as short as a nanosecond.

In phosphorescene time dealy is more from seconds to minutes .

True or both processes :

b) Photon absorption usually occurs when a molecule is in an excited singlet electronic state.