L6 Rich: Fluorescence Spectroscopy Flashcards Preview

1st Year sem 2 : Forensic Analysis > L6 Rich: Fluorescence Spectroscopy > Flashcards

Flashcards in L6 Rich: Fluorescence Spectroscopy Deck (24):
1

what is dissociation?

Breaks into fragments

2

whats re-emission?

Reverse of absorption process

3

whats non-radiative decay?

Energy transferred to surrounding molecules

4

whats radiative decay?

Combination of re-emission and non-radiative decay

5

what's ground state?

before energy is absorbed

6

How does a molecule go from ground state to excited sate?

absorbs energy

7

in what ways can energy be lost?

dissociation
re-emission
non-radiative decay
radiative decay

8

what is radiation less dissipation ?

non radiative decay

9

what are the two radiative decay processes?

fluorescents, phosphorescence

10

in florescence what do we Start with?

initial absorption

11

how does florescence radiative decay processe work?

initial absorption, excited electronic state, then it collides with surrounding molecules, stepping down different vibrational energy levels, then emit lights at a lower frequency than incident radiation.

12

is fluorescence a quick process?

yes

13

what's a fluorescence lifetimes?

typically 10^-8 seconds

14

what's the most common use of fluorescence?

fluorescence dyes

15

what are the steps for phophorescence?

initial absorption, excited electronic state, energy lost through collisions etc, steps down vibrational levels, energy level lost like this until gap too big.

16

phophorescence has a ____ state.

triplet

17

what does a triplet state allow?

unpairing of electrons, they can point in the same direction

18

what are the steps for phosphorescence after the big gap?

Cant drop to ground state because it's in the triplet state, spin forbidden. looses energy slowly

19

what's a phosphorescence lifetimes?

seconds minutes hours

20

what's a useful aspect of phosphorescence ?

anything that glows in the dark

21

what's a useful aspect of phosphorescence ?

anything that glows in the dark

22

where can fluorescence be applied?

optical brightness
fingerprint visualisation
metal cation determination

23

what did fabric washing companies do?

added optical brightness to make it white

24

what is optical brightness added too?

fabric washing
paper