Results 1 - 10 of 24
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[en] In the present work, we shed light on a new excited state intermolecular dynamical mechanism for 2-(4′-N, N-Dimethylaminophenyl)imidazo[4,5-b]pyridine (DMAPIP) in methanol (MeOH) solvent. Given intermolecular hydrogen bond connection modes, we confirm that DMAPIP-2MeOH (two MeOH molecules connecting with DMAPIP system) is the most stable and reasonable form in both S0 and S1 states rather than DMAPIP-MeOH. Further, we make a new attribution that excited state multiple protons transfer (ESMPT) process can occur with a low potential barrier in the S1 state for DMAPIP-2MeOH, and rotation process of twisting dimethylamino or dimethylaminophenyl moiety is nonexistent. Our work not only clarifies how to judge numbers of solvent molecules participating in ESMPT reaction, but paves the way for further investigating intermolecular multiple hydrogen bonds interactions in biological field.
[en] Using quasi-classical trajectory method, we have studied the dynamical properties of O(3p) + DCl→OD + Cl reaction on the 3A″ potential energy surface over the collision energy range of 14∼20 kcal/mol. The integral cross section increases with the increase of the collision energy. Strongly inverted vibrational distributions and dominated backward scattering of OD are observed. OD products show rotationally hot and vibrationally cold distributions. Little influence of the collision energy on the product rotational alignment is also found. (authors)
[en] It is shown that the propagator and wave function recently found by Yeon et al. [Phys. Rev. A 68, 052108 (2003)] are not complete and the results are not correct for constant coefficients of a time-dependent general quantum quadratic Hamiltonian for the case of γ=0. We presented the correct evolution operator, propagator, and wave function of the general time-dependent quantum quadratic Hamiltonian system
[en] In this work, the effects of quantum interference and spontaneously generated coherence (SGC) are theoretically analyzed in a four-level system of a 87Rb atom. For the effects of SGC, we find that a new kind of electromagnetically induced transparency channel can be induced due to destructive interference, and the nonlinear Kerr absorption can be coherently narrowed or eliminated under different strengths of the coupling and switching fields.
[en] We present the theory of coherent optical spectroscopy for single quantum dot under the pump-probe driving. We generally study the line shapes, Mandel's Q parameters, and few photon emission probabilities of single quantum dot system. The probe signals demonstrate the Autler-Townes splitting effect, and the first moment of our results confirms recent experimental results [Xu et al., Science 317, 929 (2007)]. We show that the pump and probe fields modify the emission photon statistical properties and control emission photon properties.
[en] We investigate the chaotic dynamics of normal mode molecules from the classical point of view using the coupling Morse oscillators. New interesting phenomena of the fractured tori and the cross of tori on the Poincar-section, which go against our traditional understanding, are found and investigated. Also, we find that the phenomenon of tori cross is a signature of the single bond's energy beyond the total vibrational energy. Finally, a method to improve this scarcity is proposed. (authors)
[en] The algebraic Hamiltonian for a triatomic molecule can be obtained by using dynamical Lie algebra method (the expansion coefficients are obtained by fitting spectroscopic data). Triatomic molecular potential energy surface (PES) is obtained by using coherent state to take the classical limits of algebraic Hamiltonian. This PES is applied to H2O molecule, and the deduced force constant is in good agreement with the experimental data
[en] Highlights: • We extended the short-time Chebyshev wave packet method the calculation of photoionization dynamics. • This method is much suited for dealing with large sparse Hamiltonian matrix. • Our study provides a new way for understanding the molecular ionization process. In this letter we present the extended usage of short-time Chebyshev wave packet method in the laser induced molecular photoionization dynamics. In our extension, the polynomial expansion of the exponential in the time evolution operator, the Hamiltonian operator can act on the wave packet directly which neatly avoids the matrix diagonalization. This propagation scheme is of obvious advantages when the dynamical system has large Hamiltonian matrix. Computational simulations are performed for the calculation of photoelectronic distributions from intense short pulse ionization of K2 and NaI which represent the Born–Oppenheimer (BO) model and Non-BO one, respectively.
[en] We study the dynamical entanglement of vibrations, intramolecular energy transfer and coherence properties in triatomic molecular systems based on discrete self-trapping theory. O3 and SO2 samples are employed as typical local-mode (LM) and normal-mode molecules, respectively. It is demonstrated that the LM molecule prepared in a LM characteristic state is much more suitable to realize quantum computation. In addition, by introducing a section of entanglement and energy transfer, we investigate the relationship between the two quantities generally. The dynamics between entanglement and energy transfer can reveal a good synchronism under some conditions. Moreover, the intramolecular coherence properties presented by the coherence visibility are discussed in some cases. (paper)
[en] O(1D) + HCl(v = 0; j = 0) → ClO + H and its isotope exchange reaction O(1D) + DCl(v = 0; j = 0) → ClO + D are studied in the collision energy range 14.0-20.0 kcal/mol based on the potential energy surface 1A′ state. Reaction probabilities, integral cross sections, the two angular distribution functions (concerning the initial/final velocity vector, and the product rotational momentum vector), and the product rotational alignment parameters are calculated as a function of the collision energy for the two reactions. The four generalized polarization dependent differential cross sections are presented to manifest the polarization characters. Also, the effect of the collision energy and the kinetic isotope effect are studied. (author)