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黒崎 譲; Ho, T.-S.*; Rabitz, H.*
Chemical Physics, 469-470, p.115 - 122, 2016/05
被引用回数：2 パーセンタイル：6.19(Chemistry, Physical)The prospect of performing the open 
cyclic ozone isomerization has attracted much research attention. Here we explore this consideration theoretically by performing quantum optimal control calculations to demonstrate the important role that excited-state dissociation channels could play in the isomerization transformation. In the calculations we use a three-state, one-dimensional dynamical model constructed from the lowest five 
A' potential energy curves obtained with high-level 
calculations. Besides the laser field-dipole couplings between all three states, this model also includes the diabatic coupling between the two excited states at an avoided crossing leading to competing dissociation channels that can further hinder the isomerization process. The present three-state optimal control simulations examine two possible control pathways previously considered in a two-state model, and reveal that only one of the pathways is viable, achieving a robust 
95% yield to the cyclic target in the three-state model.
黒崎 譲; Ho, T.-S.*; Rabitz, H.*
Journal of Chemical Physics, 140(8), p.084305_1 - 084305_11, 2014/02
被引用回数：6 パーセンタイル：22.18(Chemistry, Physical)We construct a two-state one-dimensional reaction-path model for ozone open cyclic isomerization dynamics. The model is based on the intrinsic reaction coordinate connecting the cyclic and open isomers with the O
+ O asymptote on the ground-state 
' potential energy surface obtained with the high-level method. Using this two-state model time-dependent wave packet optimal control simulations are carried out. Two possible pathways are identified along with their respective band-limited optimal control fields; for pathway 1 the wave packet initially associated with the open isomer is first pumped into a shallow well on the excited electronic state potential curve and then driven back to the ground electronic state to form the cyclic isomer, whereas for pathway 2 the corresponding wave packet is excited directly to the primary well of the excited state potential curve. The simulations reveal that the optimal field for pathway 1 produces a final yield of nearly 100% with substantially smaller intensity than that obtained in a previous study using a single-state one-dimensional model. Pathway 2, due to its strong coupling to the dissociation channel, is less effective than pathway 1. The simulations also show that nonlinear field effects due to molecular polarizability and hyperpolarizability are small for pathway 1 but could become significant for pathway 2 because much higher field intensity is involved in the latter.
黒崎 譲; Artamonov, M.*; Ho, T.-S.*; Rabitz, H.*
Journal of Chemical Physics, 131(4), p.044306_1 - 044306_8, 2009/07
被引用回数：25 パーセンタイル：65.36(Chemistry, Physical)Quantum optimal control simulations have been carried out molecular isomerization dynamics of a one-dimensional (1D) reaction-path model involving a dominant competing dissociation channel. The 1D intrinsic reaction coordinate model mimics the ozone open cyclic ring isomerization along the minimum energy path that successively connects the ozone cyclic ring minimum, the transition state (TS), the open (global) minimum, and the dissociative O + O asymptote on the O
ground-state 1A' potential energy surface. The molecular orientation of the modeled ozone is held constant with respect to the laser-field polarization and several optimal fields are found that all produce nearly perfect isomerization. The optimal control fields are characterized by distinctive high temporal peaks as well as low frequency components, thereby enabling abrupt transfer of the time-dependent wave packet over the TS from the open minimum to the targeted ring minimum.
)の異性化反応の制御黒崎 譲; Artamonov, M.*; Ho, T.-S.*; Rabitz, H.*
no journal, ,
本研究では、オゾン(O)のopen体をring体へ異性化させ得る最適なレーザー場を最適制御理論(OCT)により求めることを目的としている。ポテンシャル面は基底状態のみを考慮し、最小エネルギー経路に基づく一次元モデルを用いた。OCT計算の結果、1に近い確率で異性化を起こし得るレーザー場を見いだすことができた。計算結果の解析により、O+Oへの解離を避けてring体へ異性化するために系は反応障壁をすばやく乗り越えなければならず、このため反応障壁に達する直前でレーザー場の強度が急激に増大する必要があることが明らかとなった。
黒崎 譲; Ho, T.-S.*; Rabitz, H.*
no journal, ,
本研究では、ポテンシャルの交差点での非断熱遷移過程が含まれる反応を効率的に制御するレーザー場を、最適制御理論(OCT)により求めることを目的とする。ここでは、オゾン分子(O)のopen-ring異性化を例として、経路の途中で交差する二状態のポテンシャル曲線からなる一次元モデルを用いる。OCT計算の結果、約86%の確率でopenからringへの異性化を起こし得るレーザー場が見いだされた。これは、以前基底状態のみを考慮したモデルポテンシャルを用いた場合に得られたレーザー場と比べ、最大強度は1/3程度であり、より現実的なものとなっている。
黒崎 譲; Ho, T.-S.*; Rabitz, H.*
no journal, ,
電場の存在下では、一般に分子の双極子モーメントが誘起される。この効果は特に電場が強い場合に顕著となり、理論計算の際にハミルトニアンに非線形項を加える必要が生じてくる。本研究では、オゾン分子(O)のopen-cyclic異性化の量子制御を例として、非線形電場効果の影響を理論的に考察する。最適制御理論に基づく計算の結果、非線形効果を考慮した場合、最適電場のスペクトルには静電場(ゼロ周波数成分)の寄与が非常に大きいことが明らかとなった。これは、同効果を無視した場合には見られなかった結果である。
