Rotational Population Measurement of Ultracold 85Rb^133Cs Molecules in the Lowest Vibrational Ground State

We measure the rotational populations of ultracold SS Rbla3 Cs molecules in the lowest vibrational ground state by a depletion spectroscopy and quantify the molecular production rate based on the measurement of single ion signal area. The SSRb133Cs molecules in the X1∑＋（v = 0） are formed from the short-range （2）^3П0＋（V = 10, J = 0） molecular state. A home-made external-cavity diode laser is used as the depletion laser to measure the rotational populations of the formed molecules. Based on the determination of single ion signal, the production rates of molecules in the J=0 and J = 2 rotational levels are derived to be 4800mole/s and 7200mole/s, respectively. The resolution and quantification of molecules in rotational states are facilitative for the manipulation of rotational quantum state of ultracold molecules.

Implementation of ternary Shor's algorithm based on vibrational states of an ion in anharmonic potential

It is widely believed that Shor＇s factoring algorithm provides a driving force to boost the quantum computing research.However, a serious obstacle to its binary implementation is the large number of quantum gates. Non-binary quantum computing is an efficient way to reduce the required number of elemental gates. Here, we propose optimization schemes for Shor＇s algorithm implementation and take a ternary version for factorizing 21 as an example. The optimized factorization is achieved by a two-qutrit quantum circuit, which consists of only two single qutrit gates and one ternary controlled-NOT gate. This two-qutrit quantum circuit is then encoded into the nine lower vibrational states of an ion trapped in a weakly anharmonic potential. Optimal control theory（OCT） is employed to derive the manipulation electric field for transferring the encoded states. The ternary Shor＇s algorithm can be implemented in one single step. Numerical simulation results show that the accuracy of the state transformations is about 0.9919.

AN SCF-CI STUDY OF HIGHLY EXCITED VIBRATIONAL STATES OF BENT TRIATOMIC MOLECULES AND ITS APPLICATION TO O_(3)

A self-consistent-field—configuration interaction(SCF-CI)procedure of studying highly excited vibrational states of bent triatomic molecules is suggested and its application to O_3 is investigated.

Molecular Dynamics Simulations of Silica Nanotube： Structural and Vibrational Properties Under Different Temperatures

Four-, six-, and eight-membered ring silica nanotubes at temperatures from 300 K to 1600 K are relaxed by classical molecular dynamics simulations with three potential models. The simulation results indicate that the stability of the end rings of the three silica nanotubes gradually decreases with increase in temperature. The validity of the vibrational features of silica nanotubes is shown by the vibrational density of states. Infrared spectra on the silica nanotubes under different temperatures are investigated. A detailed assignment of each spectral peak to the corresponding vibrational mode of the three nanotubes has been addressed. The results are in good agreement with the other theoretical and experimental

Steering Vibrational Population Transfer via Double-∑-Type Laser Scheme

The vibrational state-selected population transfer from a highly vibrationally excited level to the ground level is of great importance in the preparation of ultra-cold molecules. By using the time-dependent quantum-wave-packet method, the population transfer dynamics is investigated theoretically for the HF molecule. A double-E-type laser scheme is proposed to transfer the population from the ｜v=16〉 level to the ground vibrational level ｜v=0〉 on the ground electronic state. The scheme consists of two steps： The first step is to transfer the population from ｜v=16〉 to ｜v=7〉 via an intermediate level ｜v=11〉, and the second one is to transfer the population from ｜v=7〉 to ｜v=0〉 via ｜v=3〉. In each step, three vibrational levels form a E-type population transfer path under the action of two temporally overlapped laser pulses. The maximal population-transfer efficiency is obtained by optimizing the laser inten- sities, frequencies, and relative delays. Cases for the pulses in intuitive and counterintuitive sequences are both calculated and compared. It is found that for both cases the population can be efficiently （over 90%） transferred from the ｜v=-16〉 level to the ｜v=0〉 level.

Crossed Molecular Beam Study of H＋CH4 and H＋CD4 Reactions： Vibrationally Excited CH3/CD3 Product Channels

We study the H＋CH4/CD4-＋H2/HD＋CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the （2＋1） resonance enhanced multi-photon ionization （REMPI） detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.

Study of highly excited vibrational dynamics of HCP integrable system with dynamic potential methods

Highly excited vibrational dynamics of phosphaethyne(HCP)integrable system are investigated based on its dynamic potentials.Taking into consideration the 2:1 Fermi resonance between H–C–P bending vibrational mode and C–P stretching vibrational mode,it is found that the effects of H–C stretching vibrational mode on vibrational dynamic features of the HCP integrable system are significant and regularly vary with Polyad numbers(P number).The geometrical profiles of the dynamic potentials and the corresponding fixed points are sensitive to the variation of H–C stretching vibrational strength when P numbers are small,but are not sensitive when P numbers become larger and the corresponding threshold values become lower.The phase space trajectories of different energy levels in a designated dynamic potential(P=28)were studied and the results indicated that the dynamic potentials govern the various dynamic environments in which the vibrational states lie.Furthermore,action integrals of the energy levels contained in dynamic potential(P=28)were quantitatively analyzed and elucidated.It was determined that the dynamic environments could be identified by the numerical values of the action integrals of trajectories of phase space,which is equivalent with dynamic potentials.

Ab initio calculations on the α^3∑u^＋ state properties of dimer ^7Li2

The comparison between single-point energy scanning （SPES） and geometry optimization （OPT） in determining the equilibrium geometry of the α^3∑u^＋ state for ^7Li2 is made at numerous basis sets such as 6-311＋＋G（2df）, cc-PVTZ, 6-311＋＋G（2df, p）, 6-311G（3df,3pd）, 6-311＋＋G（2df,2pd）, D95（3df,3pd）, 6-311＋＋G, DGDZVP, 6-311＋＋G（3df,2pd）, 6-311G（2df,2pd）, D95V＋＋, CEP-121G, 6-311＋＋G（d,p）, 6-311＋＋G（2df, pd） and 6-311＋＋G（3df,3pd） in full active space using a symmetry-adapted-cluster/ symmetry-adapted-cluster configuration-interaction （SAC/SAC=CI） method presented in Gaussian03 program package. The difference of the equilibrium geometries obtained by SPES and by OPT is reported. Analyses show that the results obtained by SPES are more reasonable than those obtained by OPT. We have calculated the complete potential energy curves at those sets over a wide internuclear distance range from about 3.0α0 to 37.0α0, and the conclusion is that the basis set cc-PVTZ is the most suitable one. With the potential obtained at ccopVTZ, the spectroscopic data （Te, De, D0, ωe,ωeХe, αe and Be） are computed and they are 1.006 eV, 338.71 cm^-1, 307.12 cm^-1, 64.88 cm^-1, 3.41 cm^-1, 0.0187 cm^-1 and 0.279 cm^-1, respectively, which are in good agreement with recent measurements. The total 11 vibrational states are found at J=0. Their corresponding vibrational levels and classical turning points are computed and compared with available RKR data, and good agreement is found. One inertial rotation constant （By） and six centrifugal distortion constants （Dr Hv, Lv, My, Nv, and Ov） are calculated. The scattering length is calculated to be -27.138α0, which is in good accord with the experimental data.

Quasiclassical Trajectory Study of Collisional Energy Transfer between Highly Excited C_6F_6 and N_2 ,O_2 and Ground State C_6F_6

Quasiclassical trajectory calculation (QCT) is used frequently for studying collisional energy transfer between highly vibrationally excited molecules and bath gases. In this paper, the QCT of the energy transfer between highly vibrationally excited C6F6 and N2 ,O2 and ground state C6F6 were performed. The results indicate that highly vibrationally excited C6F6 transferred vibrational energy to vibrational distribution of N2, O2 and ground state C6F6, so they are V-V energy transfer. Especially it is mainly V-V resonance energy transfer between excited C6F6 and ground state C6F6, excited C6F6 transfers more vibrational energy to ground state C6F6 than to N2 and O2 . The values of QCT , -〈DEvib〉of excited C6F6 are smaller than those of experiments.

Theoretical Study on the Potential Energy Curve and Vibration-rotation Spectra of BeF Radical

The potential energy curve （PEC） of BeF（X2Σ＋） radical is investigated by using the complete active space self-consistent field （CASSCF） method followed by the highly accurate valence internally contracted multireference configuration interaction （MRCI） approach over the internuclear separation range from 0.0522 to 2.0472 nm. The PEC is fitted to the analytic Murrell-Sorbie function, which is employed to accurately determine the spectroscopic parameters. The present D0, De, Re, ωe, ωeχe, αe and Be are 6.14 eV, 6.22 eV, 0.1372 nm, 1236.12 cm-1, 9.11 cm-1, 0.0175 cm-1 and 1.4651 cm-1, respectively. These parameters have been compared with those of previous investigations reported in the literature. With PEC determined at the present level of theory, a total of 75 vibrational states have been predicted for the first time by numerically solving the radial Schrdinger equation of nuclear motion using the Numerov method. For each vibrational state, the complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined for the first time. Comparing with the available experiments and other theories, we find that the present spectroscopic parameter and molecular constant results are more accurate and complete than the previous theoretical investigations.

Generation of Arbitrary Pure States for Three-dimensional Motion of a Trapped Ion

In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate vibrational sidebands with respect to the appropriate electronic transition.

Vibrational state distribution of cations induced by tunneling ionization of carbon monoxide in femtosecond strong laser fields

We experimentally investigate the vibrational state distribution of the cations after carbon monoxide(CO)molecules are irradiated by strong laser fields.Vibrational-resolved fluorescent spectrum is observed,which can be well assigned as the A^(2)Π(υ′=0-3)→X^(2)Σ+(υ″=0-3)transitions of the cations CO+,indicating the strong field ionization of the inner molecular orbital of CO.Relative distribution of vibrational states A^(2)Π(υ′=0-3)of CO+is retrieved from the measured spectrum and the Franck-Condon factors.It is found that the vibrational state distribution in strong field ionization of CO apparently deviates from the Franck-Condon-like distribution,but is in good agreement with the calculations,in which we include both the ionization rate and the overlapping between the vibrational wavefunctions of the neutral and cationic electronic states.The distribution of CO+(A^(2)Π,υ′)strongly depends on the laser intensity but is less dependent on the laser ellipticity.Analysis indicates the inter-nuclear distance-dependent ionization plays a significant role in the vibrational state distribution induced by strong field ionization of CO molecules.

低温等离子体转化CO_(2)及分解机理研究

如何实现CO_(2)循环和高效利用已成为环境领域亟须解决的热点问题。低温等离子体(low-temperature plasma,LTP)技术因其独特的非平衡优势,可以在大气压常温条件下高效打破C=O双键,为实现CO_(2)高效转化提供了新方案。然而,如何提高等离子体催化CO_(2)的转化率及能量效率仍须深入研究。该综述首先总结了当前国内外不同类型的LTP转化CO_(2)的研究进展,通过分析LTP作用CO_(2)的分解机理,揭示了单独等离子体作用下转化率和能量效率难以同时提升的关键机制,在此基础上,总结了催化剂与等离子体的协同效应,并分析了催化剂的引入对转化率及能量效率的影响。最后,指出了低温等离子体催化CO_(2)转化未来的研究重点。

H_(2)S第一吸收带振动激发态光解动力学的理论研究

本文利用切比雪夫实波包法研究了不同初始振动态下H_(2)S第一吸收带的光解量子动力学。由于初始振动态的波函数不同,计算得到的吸收光谱以及产物的振动态分布表现出不同的动力学特性,由于角坐标波函数的变化,初始伸缩振动激发态(1,0,0)和(0,0,1)的吸收光谱宽度和峰值与振动基态不同,而(0,1,0)振动态的吸收光谱中有两个几乎同样高的峰值.(0,1,0)态的产物振动态分布对激发能量的依赖不强,并由V=0的产物主导,但在(1,0,0)和(0,0,1)振动态的较低能量处占主导的产物是SH(X,V=1)碎片,产物的转动态分布对总能量的依讨赖性较弱,且分布非常冷并在j=1处达到峰值,但(0,1,0)振动态的转动态分布表现出明显的振荡,其各向异性参数随转动量子数的振荡行为不同于其他三种振动态的各向异性参数.

Density of excess modes below the first phonon mode in four-dimensional glasses

Glasses are known to possess low-frequency excess modes beyond the Debye prediction.For decades,it has been assumed that evolution of low-frequency density of excess modes D(ω) with frequency ω follows a power-law scaling:D(ω)~ω~γ.However,it remains debated on the value of γ at low frequencies below the first phonon-like mode in finitesize glasses.Early simulation studies reported γ=4 at low frequencies in two-(2D),three-(3D),and four-dimensional(4D)glasses,whereas recent observations in 2D and 3D glasses suggested γ=3.5 in a lower-frequency regime.It is uncertain whether the low-frequency scaling of D(ω)~ω^(3.5) could be generalized to 4D glasses.Here,we conduct numerical simulation studies of excess modes at frequencies below the first phonon-like mode in 4D model glasses.It is found that the system size dependence of D(ω) below the first phonon-like mode varies with spatial dimensions:D(ω) increases in2D glasses but decreases in 3D and 4D glasses as the system size increases.Furthermore,we demonstrate that the ω^(3.5)scaling,rather than the ω~4 scaling,works in the lowest-frequency regime accessed in 4D glasses,regardless of interaction potentials and system sizes examined.Therefore,our findings in 4D glasses,combined with previous results in 2D and 3D glasses,suggest a common low-frequency scaling of D(ω)~ ω^3.5) below the first phonon-like mode across different spatial dimensions,which would inspire further theoretical studies.

Na_2高位振动态与Ar,N_2碰撞中模温度的变化

利用受激发射泵浦激发Na2分子,使Na2[X1∑+g(ν″=33,J″=11)]得到布居,研究了高振动激发态Na*2与Ar和N2的碰撞弛豫过程.由激光诱导荧光得到Na2(ν≤33)各振动能级的时间分辨布居分布,从而得到Boltzmann振动温度和转动温度随时间的变化.对于Na*2与Ar碰撞,在泵浦-探测延迟时间tD=8μs前,振动温度Tvib减小很慢;在8-12μs间,Tvib迅速下降并达到平衡.而转动温度Trot和平移温度Ttran在Tvib迅速下降时才开始缓慢增加.对于Na*2与N2碰撞,Tvib存在三个变化阶段,先是迅速下降,然后下降减缓,最后减小很慢并达到平衡.而在整个过程中,Trot和Ttran一直是很缓慢地增加.实验数据说明了弛豫过程是分阶段进行的,单一速率系数不能正确解释复杂的弛豫过程,并会丢失平衡过程中的关键特点.

高振动激发态吡嗪碰撞传能的QCT计算研究

用准经典轨线(QCT)方法计算了高振动激发态吡嗪(C4N2H4)与N2、O2、NH3、基态吡嗪之间的碰撞传能.C4N2H4通过计算发现,高振动激发态C4N2H4与N2、O2碰撞发生的主要是V鄄V传能,与NH3碰撞发生的主要是V鄄R传能,与基态C4N2H4碰撞发生的主要是V鄄V(R)传能.通过比较高振动激发态C4N2H4、C6F6、C6H6与其基态分子的碰撞传能,发现此类碰撞传能中,若分子的对称性高,则V鄄V传能更容易实现.

C_2H_4-K体系中振动态至电子态传能的研究

用TEACO2激光将C2H4分子激发到高振动激发态，高振动激发态的C2H4分子与基态的K原子碰撞发生振动态→电子态（V→E）传能过程，根据提出的能级组模型，对测得的时间分辨原子荧光信号进行处理，获得温度在453－663K范围内，C2H4－K体系中V→E传能速率的数量级为10－10／cm3·molecule－1·s－1，对应的碰撞传能截面约为30～80A2．随着反应温度升高，V→E传能截面减小．上述实验结果表明碰撞体间吸引相互作用在这种非共振的V→E传能过程中起主要作用．利用多极相互作用势下的碰撞络合物模型对实验结果进行了讨论．