The molecular orientation created by laser fields is important for steering chemical reactions. In this paper, we propose a theoretical scheme to manipulate field-free molecular orientation by using an intense super-G...The molecular orientation created by laser fields is important for steering chemical reactions. In this paper, we propose a theoretical scheme to manipulate field-free molecular orientation by using an intense super-Gaussian laser pulse and a time-delayed terahertz half-cycle pulse(THz HCP). It is shown that the degree of field-free orientation can be doubled by the combined pulse with respect to the super-Gaussian pulse or THz HCP alone. Moreover, different laser intensities, carrier envelop phases, shape parameters, and time delays have great influence on the positive and negative orientations, with other conditions unchanged. Furthermore, it is indicated that the maximum degree and direction of molecular orientation can be precisely controlled by half of the duration of the super-Gaussian pulse. Finally, by adjusting the laser parameters of the super-Gaussian laser pulse and THz HCP, the optimal results of negative orientation and corresponding rotational populations are obtained at different temperatures of the molecular system.展开更多
The effects of the characteristics of molecules and external fields on field-free molecular orientation are investigated through the comparison of HBr with LiH driven by the combination of a two-color laser pulse and ...The effects of the characteristics of molecules and external fields on field-free molecular orientation are investigated through the comparison of HBr with LiH driven by the combination of a two-color laser pulse and a time-delayed THz laser pulse. It is shown that the dipole interaction has greater influence on field-free orientation than the hyperpolarizability interaction. In addition to the temperature dependence of orientation degree, the effects of the amplitudes of the two-color laser pulse and THz laser pulse, rising time, and THz laser frequency on molecular orientation are also discussed.展开更多
The field-free alignment of molecule Cl CN is investigated by using a terahertz few-cycle pulse(THz FCP)based on the time-dependent density matrix theory.It is shown that a high degree of molecular alignment can be ob...The field-free alignment of molecule Cl CN is investigated by using a terahertz few-cycle pulse(THz FCP)based on the time-dependent density matrix theory.It is shown that a high degree of molecular alignment can be obtained by changing the matching number of the THz FCPs in the adiabatic regime and the non-adiabatic regime.The matching number can affect both the maximum value of the alignment and the time at which it is achieved.It is also found that a higher degree of alignment can be achieved by using the THz FCP at lower intensity and there exists an optimal threshold of molecular alignment with the increase of the field amplitude.Also found is the frequency sensitive region in which the degree of maximum alignment can be enhanced greatly by modulating the center frequencies of different THz FCPs.The investigation demonstrates that comparing with a THz single-cycle pulse,a better result of the field-free alignment can be created by a THz FCP at a constant rotational temperature of molecule.展开更多
Potential energy curves （PECs） for the ground state （X2∑＋） and the four excited electronic states （A2∏, B2∏, C2∑＋, 4∏） of a Bell molecule are calculated using the multi-configuration reference single and ...Potential energy curves （PECs） for the ground state （X2∑＋） and the four excited electronic states （A2∏, B2∏, C2∑＋, 4∏） of a Bell molecule are calculated using the multi-configuration reference single and double excited configuration interaction （MRCI） approach in combination with the aug-cc-pVTZ basis sets. The calculation covers the internuclear distance ranging from 0.07 nm to 0.70 nm, and the equilibrium bond length Re and the vertical excited energy Te are determined directly. It is evident that the X2∑＋, A2∏, B2∏, C2∑＋ states are bound and 4∏ is a repulsive excited state. With the potentials, all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero （J = 0） by numerically solving the radial SchrSdinger equation of nuclear motion. Then the spectroscopic data are obtained including the rotation coupling constant w e, the anharmonic constant WeXe, the equilibrium rotation constant Be, and the vibration-rotation coupling constant ae. These values are compared with the theoretical and experimental results currently available, showing that they are in agreement with each other.展开更多
Potential energy curves(PECs) for the ground state(X 2 Σ +) and the four excited electronic states(A 2 Π,B 2 Π,C 2 Σ +,4 Π) of a BeH molecule are calculated using the multi-configuration reference single and doub...Potential energy curves(PECs) for the ground state(X 2 Σ +) and the four excited electronic states(A 2 Π,B 2 Π,C 2 Σ +,4 Π) of a BeH molecule are calculated using the multi-configuration reference single and double excited configuration interaction(MRCI) approach in combination with the aug-cc-pVTZ basis sets.The calculation covers the internuclear distance ranging from 0.07 nm to 0.70 nm,and the equilibrium bond length R e and the vertical excited energy T e are determined directly.It is evident that the X2Σ+,A2Π,B2Π,C2Σ+ states are bound and 4Π is a repulsive excited state.With the potentials,all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero(J = 0) by numerically solving the radial Schr¨odinger equation of nuclear motion.Then the spectroscopic data are obtained including the rotation coupling constant ω e,the anharmonic constant ωexe,the equilibrium rotation constant Be,and the vibration-rotation coupling constant αe.These values are compared with the theoretical and experimental results currently available,showing that they are in agreement with each other.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674198 and 11874241)the Taishan Scholar Project of Shandong Province,China
文摘The molecular orientation created by laser fields is important for steering chemical reactions. In this paper, we propose a theoretical scheme to manipulate field-free molecular orientation by using an intense super-Gaussian laser pulse and a time-delayed terahertz half-cycle pulse(THz HCP). It is shown that the degree of field-free orientation can be doubled by the combined pulse with respect to the super-Gaussian pulse or THz HCP alone. Moreover, different laser intensities, carrier envelop phases, shape parameters, and time delays have great influence on the positive and negative orientations, with other conditions unchanged. Furthermore, it is indicated that the maximum degree and direction of molecular orientation can be precisely controlled by half of the duration of the super-Gaussian pulse. Finally, by adjusting the laser parameters of the super-Gaussian laser pulse and THz HCP, the optimal results of negative orientation and corresponding rotational populations are obtained at different temperatures of the molecular system.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674198)the Taishan Scholar Project of Shandong Province,Chinathe Natural Science Foundation of Shandong Province,China(Grant No.ZR2014AM002)
文摘The effects of the characteristics of molecules and external fields on field-free molecular orientation are investigated through the comparison of HBr with LiH driven by the combination of a two-color laser pulse and a time-delayed THz laser pulse. It is shown that the dipole interaction has greater influence on field-free orientation than the hyperpolarizability interaction. In addition to the temperature dependence of orientation degree, the effects of the amplitudes of the two-color laser pulse and THz laser pulse, rising time, and THz laser frequency on molecular orientation are also discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12274265 and 11874241)the Taishan Scholar Project of Shandong Province,China。
文摘The field-free alignment of molecule Cl CN is investigated by using a terahertz few-cycle pulse(THz FCP)based on the time-dependent density matrix theory.It is shown that a high degree of molecular alignment can be obtained by changing the matching number of the THz FCPs in the adiabatic regime and the non-adiabatic regime.The matching number can affect both the maximum value of the alignment and the time at which it is achieved.It is also found that a higher degree of alignment can be achieved by using the THz FCP at lower intensity and there exists an optimal threshold of molecular alignment with the increase of the field amplitude.Also found is the frequency sensitive region in which the degree of maximum alignment can be enhanced greatly by modulating the center frequencies of different THz FCPs.The investigation demonstrates that comparing with a THz single-cycle pulse,a better result of the field-free alignment can be created by a THz FCP at a constant rotational temperature of molecule.
文摘Potential energy curves （PECs） for the ground state （X2∑＋） and the four excited electronic states （A2∏, B2∏, C2∑＋, 4∏） of a Bell molecule are calculated using the multi-configuration reference single and double excited configuration interaction （MRCI） approach in combination with the aug-cc-pVTZ basis sets. The calculation covers the internuclear distance ranging from 0.07 nm to 0.70 nm, and the equilibrium bond length Re and the vertical excited energy Te are determined directly. It is evident that the X2∑＋, A2∏, B2∏, C2∑＋ states are bound and 4∏ is a repulsive excited state. With the potentials, all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero （J = 0） by numerically solving the radial SchrSdinger equation of nuclear motion. Then the spectroscopic data are obtained including the rotation coupling constant w e, the anharmonic constant WeXe, the equilibrium rotation constant Be, and the vibration-rotation coupling constant ae. These values are compared with the theoretical and experimental results currently available, showing that they are in agreement with each other.
文摘Potential energy curves(PECs) for the ground state(X 2 Σ +) and the four excited electronic states(A 2 Π,B 2 Π,C 2 Σ +,4 Π) of a BeH molecule are calculated using the multi-configuration reference single and double excited configuration interaction(MRCI) approach in combination with the aug-cc-pVTZ basis sets.The calculation covers the internuclear distance ranging from 0.07 nm to 0.70 nm,and the equilibrium bond length R e and the vertical excited energy T e are determined directly.It is evident that the X2Σ+,A2Π,B2Π,C2Σ+ states are bound and 4Π is a repulsive excited state.With the potentials,all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero(J = 0) by numerically solving the radial Schr¨odinger equation of nuclear motion.Then the spectroscopic data are obtained including the rotation coupling constant ω e,the anharmonic constant ωexe,the equilibrium rotation constant Be,and the vibration-rotation coupling constant αe.These values are compared with the theoretical and experimental results currently available,showing that they are in agreement with each other.
