Development of Methods for Predicting Second Harmonic Generation (SHG) Responses of New Infrared Nonlinear Optical (IR-NLO) Materials

Author

Katherine ColbaughFollow

Defense Date

11-14-2024

Graduation Date

Fall 12-20-2024

Availability

One-year Embargo

Submission Type

dissertation

Degree Name

PhD

Department

Chemistry and Biochemistry

School

School of Science and Engineering

Committee Chair

Jennifer A. Aitken

Committee Member

Setphanie J. Wetzel

Committee Member

Michael Van Stipdonk

Committee Member

Tomislav Pintauer

Keywords

dipole moment, NLO, f-index, SHG, infrared nonlinear optics, crystals

Abstract

Dissertation supervised by Dr. Jennifer A. Aitken.

In this work, calculations-based methods were evaluated for use in prediction of second harmonic generation (SHG), specifically χ⁽²⁾ values, of infrared nonlinear optical (IR-NLO) materials. Net dipole moment and dipole moment per volume were calculated by the bond valence sum method. Average F-index, proposed in this research, and group F-index, both representing induced dipole moment were also calculated. Each calculation was evaluated by comparing the results to single crystal and powder χ⁽²⁾ measurements of IR-NLO materials. The selected dataset consisted of ninety-six compounds including polar and nonpolar structures, newly discovered and well-established IR-NLO crystals, and compounds belonging to a range of space groups. Dipole moment calculations were shown to have a very poor correlation to single crystal χ⁽²⁾. Group F-index showed a moderate correlation to single crystal χ⁽²⁾. Average F-index was found to have a strong correlation to single crystal χ⁽²⁾ compared to a set of well-established IR-NLOs, with a 3^rd order polynomial fit with R²=0.693. The average F-index model was used to predict the single crystal χ⁽²⁾ of a set of twenty-two newly synthesized compounds by the Aitken team. Several compounds, including Cu₂ZnGeSe₄ and Li₂CdSnSe₄ were identified as promising IR-NLO candidates.

Language

English

Recommended Citation

Colbaugh, K. (2024). Development of Methods for Predicting Second Harmonic Generation (SHG) Responses of New Infrared Nonlinear Optical (IR-NLO) Materials (Doctoral dissertation, Duquesne University). Retrieved from https://dsc.duq.edu/etd/2405