The geometry optimization is carried out without any symmetry constraints and followed by vibrational fre- quency calculations. The vertical electron affinity (EAv) of cations is obtained by the difference o
However three or more atoms can give rise to more complex molecular geometry. Overall the different bonding electron pairs will arrange themselves such that repulsion between them is minimized. This is also applicable to a polyatomic cation or anion. In all cases ...
VSEPR Theory: Because nitrogen is a representative element (it resides in thepblock of the periodic table), we can predict its molecular geometry and bond angles using valence-shell electron-pair repulsion (VSEPR) theory, which basically states that electron domains will...
of procrystal electron density, as suggested by Bader et al. [39]. Computational studies The geometry optimization calculations were performed by employing the DFT functional PBE1PBE [40] in the gas phase. The hybrid PBE1PBE functional was selected based on reports that it produces geometric ...
The ab initio VASP calculations for the nominal stoichiometries include the geometry optimization of the initial structural models, enthalpies of formation, and the electronic and phonon density of states. Comparison of the chemical bonding of the structural models is performed via the electron ...
2.2. Scanning Electron Microscopy (SEM) The morphology, size, and shape of MDABCO-NH4I3 perovskite nanofibers were stud- ied using a Nova Nano SEM 200 scanning electron microscope (FEI Company, Hillsboro, OR, USA), operated at an accelerating voltage of 10 kV. Nanofibers were deposited on a...
The quality of X-ray diffraction data allowed us to find all hydrogen atoms from the ifference electron density map and refine them semi-freely using a set of suitable restraints [43]. As a result, the accurate orientations of water molecules, –NH3+ groups, and NH4+ cations were successfu...