Rotational reorientation dynamics
of cationic fluorescent dyes
in solution and in complex systems
Miklós Kubinyi
Budapest University of Technology and Economics
Aberystwyth 1982
Pump-probe laser spectroscopic
system
10000 ps
10-20 ps
DCM laser
corner cube
probe beam
sample
Ar laser
R6G laser
pump beam
detector
Transient absorption signal
ΔT ~ Fα, t 
t
a
Determination of tS1 and tor
Magic angle experiment
F54.7, t   exp  t/τS1 
Polarization dichroism experiment
  1
6
1 
 
F0, t   F90, t   exp   t 

5
  τ or τS1  
nile blue A and oxazine 170
CH3
N
C2H5
N
O
C2H5
+
NH2
HN
N
O
C2H5
NB
+
NH
C2H5
OX
DT decay curves of NB
1
1
PM
Signal
Signal
MA
0,5
0,5
0
0
0
500
Time [ps]
1000
ethanol
ethyleneglycol
0
500
Time [ps]
1000
Temperature dependence of tS1 (NB)
2000
tS1 [ps]
1500
 water
 methanol
1000
 ethanol
 ethyleneglycol
500
0
0
20
40
t [ oC]
60
80
Orientation relaxation time
τ or  τ hd  τ de
hydrodynamic
dielectric
Hydrodynamic friction
solvent viscosity
solute volume
ηVM
τ hd  fC
 τ0 .
kT
shape factor
interaction factor
0<C<1
Dielectric friction
solvent permittivity
solute dipole
4π
ε 1

τ ,
2 D
3VC kT 2ε  1
2
τ de
cavity volume
solvent relaxation time
Solvent characteristics at 20 C
Solvent
V (Å3)
43.5
60.3
34.0
71.9
16.5
72.4
acetonitrile
acetone
methanol
chloroform
water
dimethylformamide
ethanol
47.8
benzylalcohol 104.5
ethyleneglycol 59.6
 (cP)
0.36
0.326
0.597
0.58
1.002
0.80

35.77
21.34
33.64
4.72
80.21
38.43
tD (ps)
1.200
5.8
19.9
25.20
13.1
38.68
184
221
100
4
4
52
8
9
11
Isodensity surface of OX,
re = 0.0035 e/bohr3
inertia axes OX
N
2b = 9.14
O
N
N
2c = 6.32
2a = 16.12
solute properties
Solute
Nile blue A
Oxazine 720
V (Å3)
290
306
2a, 2c (Å)
4.08, 11.65
4.08, 11.97
 (D)
3.274
3.016
temperature dependence of tor
4000
ethanol
100
tor [ps]
tor [ps]
200
2
1
/T [10-3 cP/K]
 NB
 OX
3
ethylenglycol
2000
40
/T [10-3 cP/K]
80
120
viscosity dependence of tor
(exp. values)
10000
1000
1000
t or [ps]
t or [ps]
10000
100
100
OX
NB
10
10
0,1
1
10
 [cP]
100
0,1
1
10
 [cP]
100
viscosity dependence of tor
(cacd. values, SED theory)
10000
1000
1000
t or [ps]
t or [ps]
10000
100
100
OX
NB
10
10
0,1
1
10
 [cP]
100
0,1
1
10
 [cP]
100
viscosity dependence of tor
(cacd. values, shell model
10000
1000
1000
t or [ps]
t or [ps]
10000
100
100
OX
NB
10
10
0,1
1
10
 [cP]
100
0,1
1
10
 [cP]
100
solvent shell
.2 rs
2c
2a
Microscopy: CFSE stained cell
K. Suhling, Opt. Lett. 29, 584 (2004)
nile blue A in porous sol-gel glasses
R. Baumann, J. Chem. Phys. 114, 5781 (2001)