i) CC current by
excitation
iii) CA current by
excitation
iv) AC current by
excitation
,
(+)
(-)
e e
ab1 ab2
(+)
e b1b2
Rotations in the same direction
Rotations in the opposite direction
ii) AA current by
excitation
(-)
e b1b2
,
(-)
(+)
e e
ab1 ab2
Y
Z
X
L
R
Z
X
L
R
Y
Y
Z
X
L
R
Y
Z
X
L
R
L
l
R
l
iii) CA current
iv) AC current
ii) AA current
i) CC current
X
l
R
l
L
l
X
Z
L
R
X
l l
l
Z
l
L
l
R
l
Z
X
R
Z
l l
l
X
Z
L
R
Z
l l
l
X
l
R
l
L
l
X
Z
L
R
X
l l
l
parallel to Z-axis
antiparallel to X-axis
antiparallel to Z-axis
parallel to Z-axis
Resultant angular momenta and synthesized from and
Z
l
X
l
L
l
R
l
Z
l
L
=
=
=
=
+
+
+
+
(a)
(b)
OH
HO
OH
HO
OH
HO
OH
HO
Fig. 2 a The initial directional patterns of ring currents on each ring L and R induced by selective
coherent electronic excited states ða Æ b 1 Þ, ða Æ b 2 Þ and ðb 1 Æ b 2 Þ. For example, CA current
means directions of ring currents on L and R are clockwise and anticlockwise respectively.
b Resultant angular momentum l x and l z corresponding to each pattern of ring currents are plotted
respectively. l L (l R ) denotes the angular momentum created on the L(R) ring
168
H. Mineo and Y. Fujimura