Investigations into structure and properties of atomically-precise transition metal-chalcogenide clusters of CrTe and ligated Cr6Te8(PEt3)6

Author

Anthony F. Pedicini, Virginia Commonwealth UniversityFollow

DOI

https://doi.org/10.25772/HENG-JW73

Defense Date

2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Nanoscience and Nanotechnology

First Advisor

Shiv N. Khanna, PhD

Second Advisor

Everett E Carpenter, PhD

Third Advisor

Denis Demchenko, PhD

Fourth Advisor

Joseph Reiner, PhD

Abstract

The complete understanding of a clusters electronic structure, the primary mechanisms for its properties and stabilization is necessary in order to functionalize them for use as building blocks within novel materials. First principle theoretical studies have been carried out upon the electronic properties of Cr_xTe_y (x = 1 – 6, y = 0 – 8, x + y ≤ 14), as well as for the larger triethylphosphine (PEt₃) ligated cluster system of Cr₆Te₈(PEt₃)₆. Together, we aim to use the information garnered from the smaller clusters to address the underlying behavior of the ligated Cr₆Te₈(PEt₃)₆. Additionally, the properties of this larger cluster will be used to further understand its role when paired with C₆₀ within the binary cluster assembled material. The stability and macroscopic properties of the Cr₆Te₈(PEt₃)₆ cluster, have been found to be sensitive to type of passivating ligand.

As will be shown, the ground state structures of Cr_n atoms are sensitive to both the number and position of bonded Te atoms. Moreover, that this sensitivity carries over into larger cluster sizes, and at several size intervals produces clusters with high magnetization. To this, we add the investigation into the manipulation of the Cr₆Te₈ cluster geometry and its properties through various ligands, such as PH₃, CO, and CN. It will show, that in altering these ligands there is a modification to the clusters valence shell count, which in turn alters its ionization potential and electron affinity. Additionally, although the ionization potential and electron affinity have changed for the Cr₆Te₈(PEt₃)₆ cluster, it has been found that its high magnetization does not.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

7-13-2017