Convergence of electric field and electric field gradient versus atomic basis sets in all‐siliceous and Mg substituted phillipsites

Abstract

Electrostatic potential (EP), electric field (EF), and electric field gradient (EFG) values are calculated in periodic models of magnesium substituted phillipsite (MgPHI) zeolite forms using periodic DFT (PDFT) hybrid B3LYP level with fourteen different basis sets. Relative root mean square differences between the EP, EF, or EFG values estimated between different basis sets are evaluated in several spatial domains available for adsorbate molecules in the zeolite. In these areas, the EF increase in MgPHI is evaluated relative to all-siliceous PHI types. The EP is interpreted in terms of framework ionicity for MgPHI and all-siliceous PHI models. Angular Si-O-Si dependence of the EFG asymmetry at (17)O atoms in all-siliceous zeolites is discussed.

Point atomic multipole moments for simulation of electrostatic potential and field in all‐siliceous zeolites

“…[20][21][22] ( Table 5). The RRMS errors of EF are larger as much as twice or even more in the classic scheme versus those in combined (Tables 4, 5, and 8).…”

“…20,22 With the 66-21G*(Si)/8-411G*(O) basis set, additional XRD types were considered such as a-quartz, cristoballite, SOD, and EPI at the B3LYP level. B3LYP was considered with 30% of Hartree2Fock exchange.…”

“…The possibilities of our calibration method need to answer two questions: (1) does the CC method work with the upper quality basis set as well? The problems of the EP and EF convergence were recently discussed; [20][21][22] therefore, the convergent (within 20% or less) EF values are provided with at least 66-21G*(Si)/66-31G*(O) basis. y20, 22 An easy determination of required basis level is thus possible now.…”

“…The problems of the EP and EF convergence were recently discussed; [20][21][22] therefore, the convergent (within 20% or less) EF values are provided with at least 66-21G*(Si)/66-31G*(O) basis. y20, 22 An easy determination of required basis level is thus possible now. (2) Could the point AMMs serve to solve other problems, such as molecular simulations?…”

“…We studied behavior of EP and EF 13,[20][21][22] versus basis sets for a series of DFT functionals. We started this series for AlPOs, 13 all-siliceous zeolites, 20 H-forms, 21 and cationic forms 22 to understand which level of basis set is necessary to achieve the EP or EF convergence if any exists. For us, it should signify the level at which we have to approximate the AMMs.…”