3E07
線形紫外レーザーパルス誘起非平面キラル分子における π 電子回転ダイナミク
スの理論的研究： コヒーレント角運動量と環電流（国立台湾大學1，国立交通大学2，東北大・理3）峯尾 浩文1，林 聖賢2，藤村 勇一2,3
Coherent π-electronic-state dynamics of chiral molecule induced byultrashort linearly polarized UV pulses: angular mometum and ring current( 1Institute of Applied Mechanics, National Taiwan University,
Taipei 106 Taiwan, 2Department of Applied Chemistry, Institute of Molecular Science
and Center for Interdisciplinary Molecular Science, National Chiao-Tung University,
Hsin-Chu 300 Taiwan, 3Department of Chemistry, Graduate School, Tohoku University,
Sendai 980-857)
Hirobumi Mineo1, Sheng H. Lin2, and Yuichi Fujimura2,3
In this work we theoretically show behaviors of ring currents in a non-planar
Chiral aromatic molecule with two phenol rings combined with a single chemical bond.
We remark that this talk is a continuous one of previous talk (3E06):
Quantum switching of –electron dynamics in optically induced nonplanar chiralaromatic molecule (P)-2,2’-biphenol, and use the same molecule.
The electrodynamics induced by a pulse laser E (t ) can be calculated bysolving the equations of motions of the density matrix:d  (t )dti V (t )  (t )   (t )V (t )    i     (t )  where Vˆ (t )     E (t ) ,  is the transition dipole moment operator.  is angularfrequency difference between two electronic states  and. The angular momentum
and ring current are given as the expectation values in terms of density matrix elements:
O (t )  n  d   d 3 r1 d 3 rn  r  r1   Tr  (t )O (r1 ) ˆOˆ (r )where n is the number of electrons, O (r )   O (r )   ,is the singleelectron operator. The angular momentum is calculated with the operatorOˆ (r )  i   x K  xK  y K  xK  n K with d   d 3 r , on the other hand the ringK  L, Re  Oˆ (r ) current is given by2mei with d   dS where n is a unit vector
K

which is perpendicular to a ring K, dS represents an integral over a surface S.
The electronic angular momentum and the resultant ring current are created bya coherent excitation of two electronic excited states using the pulse laser. Theseelectronic states belong to C2 point group which have A and B representations. As issimilar to a previous talk, in this molecular system we have three electronic excited statea(A), b1(B) and b2(B), and by changing the laser frequency we obtain two coherently
excited states a,b1 (b1,b2) which belong to different (same) symmetries. The createdring current at each chemical bond oscillates back and force by a periodicity which isgiven by the inverse of the energy gap between two coherently excited states.
()In Fig. 1 we show the directions of initially created currents by shining e ab1 ore (b1b) 2 where two coherently excited states are “in-phase”. From this figure we find thatcurrent or angular momentum transfer through the bridge chemical bond C1-C7 only
occurs if two coherently excited states belong to a different representation as is shownin Fig. 1(a). In this case the directions of ring currents and angular momenta on bothsides of phenol rings are toward opposite direction. On the other hand if two coherently
excited states belong to a same representation B shown in Fig. 1(b), the directions ofring currents and angular momenta on both sides of phenol rings are toward same
directions i.e., the created ring currents and angular momenta on both sides behave in asame manner.
(b) b1,b2 excitation(a) a, b1 excitationxx

Fig. 1 Behaviors of the ring currents are plotted where the two coherently excited statesare “in-phase”.