Lithium and oxygen interaction plays a cornerstone role in lithium ion and lithium air batteries and lithium based technologies. In this way, oxidation and reduction of neutral and charged lithium is the key process in its application as power source and sustainable energies. Since both oxidation and reduction are based on charge transfer in molecular scale, they can be analyzed via electronic structure changes. Two types of fragmentations for charged complexes were suggested, in which the positive charge was located on either lithium or oxygen fragment. Deformation density analysis is a recently developed technique for identification of different intermolecular interactions in the context of quantum chemical language. In this analysis, the molecular orbitals of isolated fragments were employed to build non-interacting and anti-symmetrized fragments and the corresponding density matrices to find deformation density matrix of each one. In the present study, two types of deformation density including kinetic energy pressure and relaxation analyses were accomplished for lithium and oxygen interaction at B3LYP/6-311+G* theoretical level. Electronic deformation orbitals responsible for charge transfer were identified with respect to their eigenvalues. The results showed how these two competed with each other in neutral and charged complexes with different fragmentations.

In the present work, an extensive theoretical calculation study on Histidine-Histidine dipeptide in gas phase is done by using DFT method with Gaussian 98 program. Through investigations on the molecular geometries of this molecule it is found that there is six rings in the molecules not two rings. The presence of four intramolecular hydrogen bonds is responsible for the formation of additional four rings besides two imidazole rings which gives more stability to the molecule. The quantum theory of atoms in molecules (QTAIM) proves these strong intramolecular hydrogen bonds in the title dipeptide.

By studying the properties of matter during heavy-ion collisions, a better understanding of the Quark-Gluon plasma is possible. One of the main areas of this study is the calculation of the magnetic field, particularly how the values of conductivity affects this field and how the field strength changes with proper time. In matching the theoretical calculations with results obtained in lab, two different models for charge density distribution inside ions is used. In this study, after explanation of some theoretical background, the magnetic field contribution of the spectators and participants in Pb-Pb ion collision is calculated in a conductive medium and vacuum. Results are compared using two different nuclear charge density models.

Understanding and accurate estimation of electrochemical parameters play a pivotal role in enhancing the performance and efficiency of electrochemical systems like batteries and fuel cells. The exchange current density and charge transfer coefficient are particularly critical factors as they are directly related to the shape and structure of the battery electrodes and influence the electrochemical processes occurring within electrodes of the battery. Considering a fixed value for these parameters for a type of battery is not accurate due to the varying shapes and structures of electrodes in different batteries. This paper presents a comprehensive mechanistic approach to determine these electrochemical coefficients based on a combination of experimental testing, one dimensional computational fluid dynamics simulation, and optimization. This study focuses on the investigation of a 4  ampere-hour lead-acid battery (IBIZA) with the determination of anodic and cathodic exchange current densities and charge transfer coefficients for both the lead and lead oxide electrodes, respectively. Mentioned parameters are derived for two scenarios (one-step constant current discharge and two-step constant current discharge). The values of  α_a, α_c and i0 for Pb and PbO2 for scenario one with 0.2 C_{rate} are found to be  1.95, 0.05, 9.99 *10^{-3}, 0.05, 1.95 and 3.05 * 10^{-4} and  with 0.2 C_{rate} are 9.98 *10^{-3}, 0.75, 1.25, 9.69 * 10^{-3}, 0.97 and 1.03, respectively.  Mentioned parameters for scenario two are found to be  0.6, 1.4, 2.70 *10^{-3}, 0.6, 1.4 and 2.40 * 10^{-4}, respectively.