AuQ+碰撞氦原子单电离的全微分截面

利用三体扭曲波计算了3.6 MeV/amu的Au^Q+ (Q=24,53)碰撞氦原子单电离的全微分截面,其结果与实验数据和其它理论进行了比较,表明全微分截面受到高电荷入射粒子的强烈影响,敲出的电子被“拖拽”沿着向前的方向. 但是,所有的理论结果都不能呈现实验上全微分截面的独特的向前峰.     

Stability and phase transition of localized modes in Bose–Einstein condensates with both two- and three-body interactions

We investigate the stability and phase transition of localized modes in Bose–Einstein Condensates (BECs) in an optical lattice with the discrete nonlinear Schrödinger model by considering both two- and three-body interactions. We find that there are three types of localized modes, bright discrete breather (DB), discrete kink (DK), and multi-breather (MUB). Moreover, both two- and three-body on-site repulsive interactions can stabilize DB, while on-site attractive three-body interactions destabilize it. There is a critical value for the three-body interaction with which both DK and MUB become the most stable ones. We give analytically the energy thresholds for the destabilization of localized states and find that they are unstable (stable) when the total energy of the system is higher (lower) than the thresholds. The stability and dynamics characters of DB and MUB are general for extended lattice systems. Our result is useful for the blocking, filtering, and transfer of the norm in nonlinear lattices for BECs with both two- and three-body interactions.     

Pressure induced phase transitions in Ga1 − x In x P

We have theoretically investigated the effect of pressure on the structural stability of GaP?:?InP mixed system. The three-body-potential (TBP) model has been used. The TBP model consists of long-range as well as short-range interactions; the long-range part includes the modified Coulomb force as well as a three-body term; the short-range part in TBP defines the van der Waals and overlap repulsive interactions. We observe a pressure-induced structural phase transformation from ZnS (B3) to NaCl (B1) type phase in Ga _1?x In _x P. Our calculated transition pressures for the initial GaP and final InP compound semiconductors are in good agreement with other reported data.     

Optimal capture trajectories using multiple gravity assists

Graph theoretic methods of optimal control in the presence of uncertainty are applied to a celestial mechanics problem. We find a fuel-efficient spacecraft trajectory which starts at infinity and is captured by the smaller member of a binary system, e.g., a moon of Jupiter, using multiple gravity assists.     

Quantum chemical investigation of the adsorption of methanol on a cluster model of faujasite

The adsorption of methanol in zeolites of the faujasite type with sodium and calcium counter ions is studied with quantum chemical methods. The zeolite is represented with a cluster model allowing calculations at the Møller-Plesset as well as the DFT level of theory. An adsorption energy of −62.4 kJ/mol is calculated at the MP2/TZVP//BP86/TZVP level of theory for one methanol molecule at one site II sodium cation. Insight into the adsorption process is obtained with a three-body decomposition which reveals a strong destabilisation of the adsorption strength by large, positive three-body terms, which is important for force field development.     

A Minimizing Property of Lagrangian Solution

In this paper, we prove that the Lagrangian solutions to the three-body problem minimize the action function. The first author is partially supported by a grant of NNSFC. The second author is partially supported by grants of MOSTC, NNSFC and QSSTF.     

可快速计算水团簇三体作用强度的新方法

将水分子视为由2个O—H键偶极构成, 再将水分子间的三体作用视为长程诱导作用和短程校正之和, 使用Thole模型计算长程诱导作用, 通过同时考虑不同水分子间的置换和同一个水分子中2个键偶极间的置换计算短程校正, 从而提出了一个可快速计算水团簇三体作用强度的新方法. 根据已报道的12347个水三聚体的结构和CCSD(T)三体作用能, 确定了该方法所需参数. 将该方法和所确定的参数应用于67个水团簇体系, 计算这些体系的三体作用能, 并与CCSD(T), MP2, M06-2X方法的计算结果进行比较. 结果表明, 相对于CCSD(T)方法的总三体作用能, 本文方法的均方根偏差(RMSD)仅为3.32 kJ/mol, 平均相对偏差(MRD)仅为2.43%; 对较大水团簇体系, 该方法计算精度稍优于MP2方法, 明显优于M06-2X方法, 并且更快捷高效.     

Superfluid phases of the three-species fermion gas

We discuss the zero temperature phase diagram of a dilute gas with three fermionic species. We make use of solvable limits to conjecture the behavior of the system in the “unitary” regions. The physics of the Thomas-Efimov effect plays a role in these considerations. We find a rich phase diagram with superfluid, gapless superfluid and inhomogeneous phases with different symmetry breaking patterns. We then discuss one particular possible experimental implementation in a system of ⁶Li atoms and the possible phases arising in this system as an external magnetic field is varied across three overlapping Feshbach resonances. We also suggest how to experimentally distinguish the different phases.     

Birth of periodic and artificial halo orbits in the restricted three-body problem

We investigate the bifurcation of artificial halo orbits from the Lyapunov planar family of periodic orbits around the collinear libration points of the circular, spatial, restricted three-body problem. Beside the gravitational forces, our model includes also the effect of the Solar Radiation Pressure (SRP) and this motivates the use of the term ‘artificial’ halo orbits. Indeed, as a typical problem, one may think of a solar sail, which is characterized by a performance parameter measuring the strength of the effect of the SRP on the spacecraft.To settle the model, we determine the position of the collinear points as a function of the mass and performance parameters and the energy values at which Hill׳s surfaces allow for transit orbits between the primaries. To analyze the dynamics we use a consolidated procedure which consists in the computation of a resonant normal form, allowing the reduction to the center manifold and providing an integrable approximation of the Hamiltonian dynamical system. Finally, we compute the bifurcation thresholds of the 1:1 resonant periodic orbit families (which have the standard ‘halo’ orbits as their first member) as a function of the performance and mass parameters.The results show that SRP is indeed a relevant ingredient for new dynamical features and must definitely be considered when planning a mission of a solar sail with trajectories in the neighborhoods of collinear points.