Ab initio study on the electronic states and laser cooling of AlCl and AlBr

We investigate whether A1C1 and A1Br are promising candidates for laser cooling. We report new ab initio calculations on the ground state X1E＋ and two low-lying states （A1H and a3H） of A1C1 and A1Br. The calculated spectroscopic constants show good agreement with available theoretical and experimental results. We also obtain the permanent dipole moments （PDMs） curve at multi-reference configuration interaction （MRCI） level of theory. The transition properties of A1H and a3H states are predicted, including the transition dipole moments （TDMs）, Franck-Condon factors （FCFs）, radiative times and radiative width. The calculated radiative lifetimes are of the order of a nanosecond, implying that they are sufficiently short for rapid laser cooling. Both A1C1 and A1Br have highly diagonally distributed FCFs which are crucial requirement for molecular laser cooling. The results demonstrate the feasibility of laser cooling A1C1 and A1Br, and we propose laser cooling schemes for A1C1 and A1Br.

Hybrid density functional study on lattice vibration,thermodynamic properties,and chemical bonding of plutonium monocarbide

Hybrid density functional theory is employed to systematically investigate the structural,magnetic,vibrational,thermodynamic properties of plutonium monocarbide（Pu C and Pu C0.75）.For comparison,the results obtained by DFT,DFT ＋ U are also given.For Pu C and Pu C0.75,Fock-0.25 hybrid functional gives the best lattice constants and predicts the correct ground states of antiferromagnetic（AFM） structure.The calculated phonon spectra suggest that Pu C and Pu C0.75 are dynamically stable.Values of the Helmholtz free energy ？F,internal energy ？E,entropy S,and constant-volume specific heat Cv of Pu C and Pu C0.75 are given.The results are in good agreement with available experimental or theoretical data.As for the chemical bonding nature,the difference charge densities,the partial densities of states and the Bader charge analysis suggest that the Pu–C bonds of Pu C and Pu C0.75 have a mixture of covalent character and ionic character.The effect of carbon vacancy on the chemical bonding is also discussed in detail.We expect that our study can provide some useful reference for further experimental research on the phonon density of states,thermodynamic properties of the plutonium monocarbide.

Quantity and Quality Equally Important in Utilizing Foreign Investment

A new round of FDI flow and new wave of international industry transfer has offered new opportunities for China to participate in international economic competition and cooperation. Utilization of foreign investment has crucial implications for enhancing China's position in the international division of labor,cultivating new competitive advantages and strengthening overall competitiveness. China should grasp the opportunity and improve the investment environment in terms of legislation,system,policy,administration and service and ensure that foreign investment plays an important role in China's economic development and promotion of independent innovation and industry upgrade.