LUMINESCENCE SPECTROSCOPY (11.0)

Question 1

optical method based on the measurement of photon by excited species

Answer 1

emission of radiation or luminescence

Question 2

provide info. on composition and amount of luminescent species

Answer 2

spectrum/ intensity released radiation

Question 3

4 features of luminescence (name)

Answer 3

1. inherent sensitivity (LOD = 1-3 orders of magnitude smaller than absorption,pbb levels
2. large linear conc. range
3. better selectivity than absorption spectroscopy
4. less widely applicable than absorption methods

Question 4

It is a type of luminescence that excitation is brought about through absorption of photons or radiation

Answer 4

fluorescence and phosphorescence

Question 5

It is a type of luminescence that excitation is brought about by chemical reaction, not by a radition source

Answer 5

chemiluminescence

Question 6

Electronic transition involves no change in electric spin (s excited to s ground)
also short lived (10^-5 s)

Answer 6

Fluorescence

Question 7

electronic transition involves a change in the electronic spin (from triple excited state to singlet ground state)
longer lifetime (10-4 - 10 s or longer); significantly less probable event than singlet/singlet transition

Answer 7

phosphorescence

Question 8

Fluorescence and absorption lines whose wavelength are identical

Answer 8

Resonance lines

Question 9

shift to longer wavelength for fluorescence lines or bands conpared with the absorption wavelengths

Answer 9

stroke’s shift