LDF method

Fig. 6. Band gap as a function of nanotube radius using first-principles LDF method. Solid line shows estimates using graphene sheet model with...

The linear combination of Gaussian-type orbitals fLCGTO) Xa method (M) is based on the local density functional (LDF) method using the Xa variant ior the exchange potential ... 

Figure 1. Band structure for all-trans conformation of unsubstituted polysilane calculated by using the LCAO-LDF method, cr-like bands are denoted with solid lines, u-like bands are denoted with dashed lines. The Fermi level is denoted as f. k represents the wave vector, and a is the length of the unit cell.

Table 2 clearly shows that the pronounced increase in intensity observed for bands C-E vs bands A-B is related to changes in photoionization cross-sections. Bands F-I were assigned to Ugand-based orbital ionizations on the basis of comparison with the UPS spectrum of PMes. Bancroft and coworkers have attributed bands A and B to ionization from orbitals with Au—C and Au—P characters, respectively, on the basis of Xa calculations and comparison with the spectrum of HgMe2. More recent calculations using the relativistic LCGTO-LDF method have provided more details about orbital compositions in AuMePMes (Table 3). They have also indicated that the role of Au6p orbitals in bonding is minimal.

While the assignment in [11] is rather tentative, the fundamentals in [10] were Identified by using the fundamentals calculated by local density functional (LDF) theory as guides. However, the assignment of Vg and Vg may have to be changed. Some combination bands and overtones were also identified force constants calculated by the LDF method were also given [10]. 

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