D * + A D + A *
Fluorescence Resonance Energy Transfer (FRET)
(D = Donor, A = Akzeptor)
k
0k k k
k k
k
k
FRET FRET ISC
IC F
FRET
FRET
FRET
= +
+ +
= + φ
0 0
,
k
k
FF
=
φ
0
,
k k
k
FRET F FRET
F
= +
Mit und φ folgt:
0 , , 0
,
,
1
1
F FRET F
F FRET F
FRET
I
− I
=
−
= φ
φ φ
D E A
λ
Fluorescence
D E A
λ
Fluorescence
FRET Efficiency, E:
6
0
1 1
E
R R
=
+
R = D-A distance R0 = Försterradius
(D-A distance where E = 50%)
0.5*R0
R0 (typical: 4-7 nm)
1.5*R0
Distance R
FRET
(E )100%
50%
0%