The isotope effects of XF （X=H, D） on the population transfer process via two-photon resonance excitation are investigated by solving the time-dependent SchrSdinger equation. The vibrational levels v=0 and 2 of the ...The isotope effects of XF （X=H, D） on the population transfer process via two-photon resonance excitation are investigated by solving the time-dependent SchrSdinger equation. The vibrational levels v=0 and 2 of the ground electronic state are taken to be the initial and target states, respectively, for the two molecular systems. The influences of the field peak amplitude and pulse duration on the population transfer process are discussed in detail. The pulse duration is required to be longer than 860 fs for the DF molecule to achieve a relatively high transfer probability （more than 80%）, while the one for the HF molecule is just required to be longer than 460 fs. Moreover, the intermediate level v=1 and the higher level v=3 may play more important roles in the two-photon resonance process for the DF molecule, compared to the roles in the process for the HF molecule.展开更多
The photodissociation dynamics of Br-C bond cleavage for BrCN in the wavelength region from 225 nm to 260 nm has been studied by our homebuilt time-slice velocity-map imaging setup.The images for both of the ground st...The photodissociation dynamics of Br-C bond cleavage for BrCN in the wavelength region from 225 nm to 260 nm has been studied by our homebuilt time-slice velocity-map imaging setup.The images for both of the ground state Br(^(2)P_(3/2))and spin-orbit excited Br^(*)(^(2)P_(1/2))channels are obtained at several photodissociation wavelengths.From the analysis of the translational energy release spectra,the detailed vibrational and rotational distributions of CN products have been measured for both of the Br and Br^(*) channels.It is found that the internal excitation of the CN products for the Br^(*) channel is colder than that for the Br channel.The most populated vibrational levels of the CN products are v=0 and 1 for the Br and Br^(*) channels,respectively.For the Br channel,the photodissociation dynamics at longer wavelengths are found to be different from those at shorter wavelengths,as revealed by their dramatically different vibrational and rotational excitations of the CN products.展开更多
In recent experiments [e.g., Nature Physics 2 （2006） 332], the enhanced light deflection in an atomic ensemble due to inhomogeneous fields is demonstrated by the electromagneticaJly induced transparency （EIT） base...In recent experiments [e.g., Nature Physics 2 （2006） 332], the enhanced light deflection in an atomic ensemble due to inhomogeneous fields is demonstrated by the electromagneticaJly induced transparency （EIT） based mechanism. In this paper, we explore a different mechanism for the similar phenomenon of the enhanced light deflection. This mechanism is based on the coherent population oscillation, which leads to the hole burning in the absorption spectrum. The medium causing the deflection of probe light is an ensemble of two-level atoms manipulated by a strong controlled field on the two photon resonances. In the large detuning condition, the response of the medium to the pump field and signal field is obtained with steady state approximation. And it is found that after the probe field travels across the medium, the signal ray bends due to the spatial-dependent profile of the control beam.展开更多
文摘The isotope effects of XF （X=H, D） on the population transfer process via two-photon resonance excitation are investigated by solving the time-dependent SchrSdinger equation. The vibrational levels v=0 and 2 of the ground electronic state are taken to be the initial and target states, respectively, for the two molecular systems. The influences of the field peak amplitude and pulse duration on the population transfer process are discussed in detail. The pulse duration is required to be longer than 860 fs for the DF molecule to achieve a relatively high transfer probability （more than 80%）, while the one for the HF molecule is just required to be longer than 460 fs. Moreover, the intermediate level v=1 and the higher level v=3 may play more important roles in the two-photon resonance process for the DF molecule, compared to the roles in the process for the HF molecule.
基金supported by the Beijing Municipal Natural Science Foundation(No.8212043)the support from Program for Young Outstanding Scientists of Institute of Chemistry,Chinese Academy of ScienceBeijing National Laboratory for Molecular Sciences。
文摘The photodissociation dynamics of Br-C bond cleavage for BrCN in the wavelength region from 225 nm to 260 nm has been studied by our homebuilt time-slice velocity-map imaging setup.The images for both of the ground state Br(^(2)P_(3/2))and spin-orbit excited Br^(*)(^(2)P_(1/2))channels are obtained at several photodissociation wavelengths.From the analysis of the translational energy release spectra,the detailed vibrational and rotational distributions of CN products have been measured for both of the Br and Br^(*) channels.It is found that the internal excitation of the CN products for the Br^(*) channel is colder than that for the Br channel.The most populated vibrational levels of the CN products are v=0 and 1 for the Br and Br^(*) channels,respectively.For the Br channel,the photodissociation dynamics at longer wavelengths are found to be different from those at shorter wavelengths,as revealed by their dramatically different vibrational and rotational excitations of the CN products.
基金The project supported by the Natural Science Foundation of China under Grant Nos. 10775048, 10704023, 10775048, and 10325523the National Fundamental Research Program of China under Grant No. 2007CB925204the Scientific Research Fund of Hunan Provincial Education Department of China under Grant No. 07C579
文摘In recent experiments [e.g., Nature Physics 2 （2006） 332], the enhanced light deflection in an atomic ensemble due to inhomogeneous fields is demonstrated by the electromagneticaJly induced transparency （EIT） based mechanism. In this paper, we explore a different mechanism for the similar phenomenon of the enhanced light deflection. This mechanism is based on the coherent population oscillation, which leads to the hole burning in the absorption spectrum. The medium causing the deflection of probe light is an ensemble of two-level atoms manipulated by a strong controlled field on the two photon resonances. In the large detuning condition, the response of the medium to the pump field and signal field is obtained with steady state approximation. And it is found that after the probe field travels across the medium, the signal ray bends due to the spatial-dependent profile of the control beam.
