Wavelengths, transition probabilities, and oscillator strengths have been calculated for M-shell electric dipole (E1) transitions in Al-like W61+ through Cl-like W57+, with partially filled 3p subshell. The fully relativistic multiconfiguration Dirac–Fock (MCDF) method, taking quantum electrodynamical effect and Breit correction into account, was used in the calculations. Calculated energy levels of M-shell excited states in Al-like through Cl-like W ions from the method were compared with some available theoretical and experimental results, and good agreement with them was achieved.

The line intensities of 0300 a—0000 s transition of the symmetric-top NH3 molecule at high temperature were obtained by directly calculating the partition functions while regarding the rotationless transition dipole moment squared as a constant. The calculated values of the total internal partition sums (TIPS) are consistent with the data of HITRAN database within 0.19% at 296 K. The calculated line intensities data at 2000 K and 3000 K are also in excellent agreement with the data in HITRAN database with discrepancies less than -0.65% and -1.77%, which strongly supports the calculations of partition function and line intensity at high temperature. Then we extended the calculation to higher temperature. The line intensities and simulated spectra of 3ν2 band of the symmetric-top NH3 molecule at 4000 K and 5000 K were reported. The results are of significance for the study of the high-temperature molecular spectra in experiment and in theory.

Based on the density functional theory DFT/ B3LYP at 6-311g level, the ground states of BeO molecule are optimized. The effects of electric field on the bond length, the system energy, the charge distribution, the energy levels, the HOMO-LUMO gaps and the infrared spectrum of BeO molecule are studied. The results indicate that the bond length of BeO molecule increass,but the system energy decreases as the external electric field increases from 0.0 to 0.05 a.u. At the same time, the energy gaps between the HOMO and LUMO become separated with the increase of electric field. It shows that the structure of BeO molecule is steady under external electric field so that oxygen atom in BeO is difficult to combine with hydrogen atom escaping from the reactor.

One-dimensional (1D) gold nanostructures have been extensively studied due to their potential applications in nanoelectronic devices. Using first-principles calculations, composites consisting of a well-defined linear Au (n = 2-4) chain encapsulated in a (9,0) single-walled carbon nanotube (SWCNT) were studied. The translational energy barrier of a single Au atom in a (9,0) SWCNT was found to be 0.03 eV. This low barrier guaranteed the formation of Au @ (9,0) SWCNT (n = 1-4) composites. Bond lengths, differential charge densities, and electronic band structures of the composites were studied. The average Au-Au bond lengths in the composites were found to be almost the same as those in the corresponding free-standing linear Au . The average bond length increased as the number of Au atoms increased. Charge transfer in all of these composites was slight, although a few valence electrons were transferred from the (9,0) SWCNT and the Au chains to intercalations. The conductivities of the encapsulated linear Au (n = 2-4) chains were enhanced to some extent by encapsulating them in the SWCNT.