Development And Applications Of Next Generation QTAIM

This dissertation is devoted to the Development and Applications of Next Generation Quantum Theory of Atoms in Molecules,which begins with the basic background of QTAIM to facilitate the understanding of the contents.The following chapter two,we have analyzing a series of five thermal electrocyclic ring-opening reactions with contrasting nuclear skeletons and activation energies.Find a new chemical topological,as opposed to energy based criterion to decide if the reactions were competitive or noncompetitive.In the way we used the QTAIM and stress tensor scalar measures and suggest that R1 and R4 reactions were noncompetitive reactions and R2,R3,and R5 were competitive reactions on basis of degeneracy results,（first goal）.In addition,find a method to distinguish torquoselectivity along the reaction coordinate of competitive and non-competitive reactions which to obtain that,introduced new measure,the bond-path framework set from QTAIM,（second goal）.Therefore found that in all five reactions the greater lengths for the bond-paths of shared-shell ring opening BCPs correctly predicted the TSIC or TSOC preferences for the experiment yield also The values were more successful at distinguishing torquoselectivity because the scalar QTAIM and stress tensor measures were only defined at BCPs and lacked a directional component.In chapter three choose the highly symmetric planar Ethene molecule to determine any dependency of the QTAIM properties on the applied E-field.In order to gain the goals in this research used next generation QTAIM to quantify the effect of a varying and directional E-field on electronic charge density of the Ethene molecule that does not significantly alter the molecular geometry.For the first time used the 3-D next generation analysis to determine the response of molecular wires in molecular electronic devices.Despite used low E-field that are accessible within experiment and do not measurably,alter the molecular geometry,significant changes to the QTAIM properties were observed.Using QTAIM,the shifting of the C-C and C-H bond critical points（BCPs）demonstrates polarization through an interchange in the size of the atoms involved in a bond,since a BCP is located on the boundary between a pair of bonded atoms.Furthermore find that for the±E_x-field,which coincides with the bond-path of the C1-C2 BCP,the associated{q,q′}path-packet shifts along with the C1-C2 BCP parallel to the direction of the±E_x-field due to the fact that there is very little spreading of the{q,q′}path-packet.In chapter four,have set out to determine the function and existence of the NNAs in small charged lithium clusters using the QTAIM and Ehrenfest Force F（r）partitioning schemes.Show that QTAIM molecular graphs all contained at least one NNA and as a consequence possessed reduced compactness.In conclusion the Ehrenfest Force partitioning have ability to smoothly follow changes in structure and therefore yield molecular graphs without conflict structures present for QTAIM and disadvantages of the Ehrenfest Force partitioning is inability to quantify delocalization ofρ（r）in the small charged lithium clusters.In addition,find that NNAs are not artifacts but it is detectable by QTAIM while Ehrenfest Force partitioning is unable to detect them due to the compactness of the Ehrenfest Force field even when applied very large Li separations.In the next following chapter five have set out to determine the origins of（NNAs）found for neutral lithium clusters Li_m（m=2-5）on the QTAIM molecular graph but not on the Ehrenfest Force F（r）molecular graph.All of the QTAIM Li_m（m=2-5）molecular graphs contained at least one NNA and none of the corresponding molecular graphs from F（r）contained NNAs.This part presents for the first time the stress tensorσ（r）on the Ehrenfest Force F（r）molecular graph.Suggested that the QTAIM（_F）presented on the Ehrenfest Force F（r）molecular graph was more similar to the Ehrenfest Force F（r）(_FAand _FB)than to the stress tensor（σF andσFH）.Finally,a few summary and outlook about the research work on the basic of this thesis are provided in chapter 6.