<s>
Rotational	B-Algorithm
correlation	I-Algorithm
time	I-Algorithm
(	O
)	O
is	O
the	O
average	O
time	O
it	O
takes	O
for	O
a	O
molecule	O
to	O
rotate	O
one	O
radian	O
.	O
</s>
<s>
In	O
solution	O
,	O
rotational	B-Algorithm
correlation	I-Algorithm
times	I-Algorithm
are	O
in	O
the	O
order	O
of	O
picoseconds	O
.	O
</s>
<s>
Rotational	B-Algorithm
correlation	I-Algorithm
times	I-Algorithm
are	O
employed	O
in	O
the	O
measurement	O
of	O
microviscosity	O
(	O
viscosity	O
at	O
the	O
molecular	O
level	O
)	O
and	O
in	O
protein	O
characterization	O
.	O
</s>
<s>
Rotational	B-Algorithm
correlation	I-Algorithm
times	I-Algorithm
may	O
be	O
measured	O
by	O
rotational	O
(	O
microwave	O
)	O
,	O
dielectric	O
,	O
and	O
nuclear	O
magnetic	O
resonance	O
(	O
NMR	O
)	O
spectroscopy	O
.	O
</s>
<s>
Rotational	B-Algorithm
correlation	I-Algorithm
times	I-Algorithm
of	O
probe	O
molecules	O
in	O
media	O
have	O
been	O
measured	O
by	O
fluorescence	O
lifetime	O
or	O
for	O
radicals	O
,	O
from	O
the	O
linewidths	O
of	O
electron	O
spin	O
resonances	O
.	O
</s>
