Lead iodide perovskites have attracted considerable interest in the upcoming photovoltaic technologies and optoelectronic devices. Therefore, an accurate theoretical description of electronic optical properties especially to understand excitonic effects this class materials is scientific practical interest. However, despite several research endeavours past, most analysis key parameters for sola...

We present a tutorial overview of the simulation of gas-phase valence-electron photoemission spectra using density functional theory (DFT), emphasizing both fundamental considerations and practical applications, and making appropriate links between the two. We explain how an elementary quantum mechanics view of photoemission couples naturally to a many-body perturbation theory view. We discuss ...

We give a detailed exposition of the formalism Kinetic Field Theory (KFT) with emphasis on perturbative determination observables. KFT is statistical non-equilibrium classical field theory based path integral formulation mechanics, employing powerful techniques developed in context quantum to describe systems. Unlike previous work KFT, we perform integration over probability distribution initia...

The physical aspect of a general perturbation theory is explored. Its role as a physical principle for understanding the interaction among the matters with different levels of hierarchy is appreciated. It is shown that the general perturbation theory can not only be used for understanding the various electronic phenomena including the nature of chemical bonds but also serve as a unified theme f...