Photochemistry Flashcards
Prompt Photodissociation
one molecule excited for each photon absorbed
so fast there is no clear excited state
Wavelength Dependence
change wavelength of irradiation change photochemistry
Delayed Photoreaction
electron excited into excited state
converted to a second excited state
then reacts
Typed of Excited State
metal centred
intraligand
ligand-metal charge transfer: need lone pair
metal-ligand charge transfer: need d electrons
metal-metal charge transfer
metal-metal bonding
Franck-Condon
absorption from one low level to many upper levels
emission from one upper level to many lower levels
0->0 same peak
mirror image spectra
Photoluminescence
light shon on a sample
Fluorescence
luminescence, no change in spin state
Phosphorescence
luminescence, change in spin state
Electroluminescence
apply potential within
out comes light
Absorption
scan wavelengths of light coming in
absorbance vs. yex
Emission
measure intensity of emission
Iem as function of yem
yex constant
Excitation
Iem as function of yex
yem constant
Selection Rules
spin
gu
asymmetric d->d
MLCT
absorption from ground state to 1(MLCT) state
emission from 3(MLCT) to ground state
Electron Transfer Redox
-ve potential, reducing
+ve potential, oxidising
Long Distance Electron Transfer
attach Ru(bpy)22+ to protein surface via histidine repeat with different histidines at known distances from haem
DNA Probe
Ru(phen)2(dppz)2+ emits in presence of DNA
intercalates in chain
Solar Battery
electricity using light
TiO2 nanoparticle
electrons into conduction band
Light Emitting Diode
cathode provides electron
anode supplies hole
Organic Light Emitting Diode
charge injection
charge transport
exciton formation
emission
Full/Empty Orbital
(t2g)0 or (t2g)6
1A1g
1 Electron or 1 Hole
(t2g)1 or (t2g)5
2T2g
2 Electrons or 2 Holes
(t2g)1(eg)1 = T1g + T2g
singlets and triplets of each
Gas Phase
one photon absorbed can cause loss of several ligands
excess energy remains and causes sequential losses
