Recent experimental works recovered multiformity of lutetium-involved dimetallofullerenes. On the basis of density functional theory (DFT) combined with statistical thermodynamic analyses, the relative stabilities of Lu 2 C 84 dimetallofullerene were clarified. Besides the experimentally acknowledged Lu 2 @ D 2d (51591)-C 84 and Lu 2 @C 2v (51575)-C 84 , another four isomers metallofullerenes, Lu 2 @C 1 (51580)-C 84 , Lu 2 C 2 @C s (39715)-C 82 , Lu 2 C 2 @C 3v (39717)-C 82 , and Lu 2 C 2 @C 2v (39718)-C 82 , are first proposed as thermodynamically stable structures. Interestingly, the geometric relationships among the pristine cages of stable Lu 2 C 84 isomers through Stone−Wales transformation or C 2 lose/ insertion reveal important clues of the fullerene formation mechanism. The ionic interaction in the stable Lu 2 C 84 isomers is revealed, and their valence states are Lu 2 4+ @C 84 4− or (Lu 2 C 2 ) 4+ @C 82 4− . In the Lu 2 @C 84 isomers, the results of frontier molecular orbital and natural bond orbital analyses suggest that a Lu−Lu single bond is formed, which is mainly composed of the 6s and 6p orbitals of the Lu atoms. Further analyses of the M 2 @C 84 (M = Sc, Y, La, and Yb) structures disclose the importance of the electron configuration of metal element toward the formation of a single metal−metal bond in C 84 . Moreover, the covalent interaction between the Lu 2 moiety and the C 84 cages is disclosed, which is a supplement to the ionic model.

We investigated the Autler-Townes splitting in photoelectron spectra of Li 2 molecules steered by ultrashort laser pulses using the time-dependent wave-packet method. Structure of the Autler-Townes splitting was presented to analyze the information of a selective population of the dressed states. It was found that population transfer process, structure of photoelectron spectrum and pattern of Autler-Townes splitting can be controlled by adjusting the intensity, wavelength and delay time of laser pulses.

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The population transfer of a NaH molecule from the ground state Σ + X 1 to the target state Σ + A 1 via stimulated Raman adiabatic passage (STIRAP) is investigated. The results show that the intensity, delay time and detuning have a significant effect on population transfer. A large population transfer is observed with increased pump and Stokes intensity, especially when the pump and Stokes intensity match. Population transfer also depends on the delay time between the pump laser pulse and the Stokes laser pulse. The detuning of the two pulses influences the population transfer. Efficient population transfer can be realized under the resonant or twophoton resonant condition.