Zachary Mayes, a doctoral candidate in chemistry, will defend their dissertation titled “Development of Dual-Scan Nuclear Magnetic Resonance (NMR) Pulse Programs for Spin-Lattice Relaxation Measurements.” Their advisor, Dr. Klaus Woelk, is an associate professor in the chemistry department.  The dissertation abstract is provided below.

This dissertation describes the development and evolution of the Split Inversion Pulse  and Recovery (SIP-R) methodology, designed to advance spin-lattice relaxation measurements in  nuclear magnetic resonance (NMR) spectroscopy. The SIP-R approach introduces a two-scan  difference spectroscopy technique utilizing a split inversion pulse sequence—the 180° inversion  pulse is split into two equal 90° pulses that can be phase-shifted with respect to each other—to  acquire spin-lattice relaxation times (T₁) with high accuracy and robustness. By employing a split  inversion pulse, SIP-R simplifies the data fitting routines for the extraction of T₁ constants and  their coefficients, requiring only two parameters in an exponential decay-to-zero functionality. In  comparison, the traditional inversion-recovery technique requires the optimization of three  parameters in a rise-to-maximum functionality to achieve the same precision. Building upon the  SIP-R framework, the SIP-R-DS and SIP-R-S adaptations were developed to incorporate  selective NMR resonance excitations. This extension targets pre-defined spectral bandwidths,  broadening the applicability of the SIP-R methodology to cross-polarization experiments and the  straightforward and unobstructed measurement of nuclear Overhauser effects (NOE). SIP-R-DS  and SIP-R-S also provide effective alternatives for molecular systems of spectral complexity or  overlapping signals by enabling tailored excitation and optimized data acquisition. To further  enhance the efficiency of SIP-R experiments, the RAPTOR (Rapid Acquisition Pulse Train to  Observe Relaxation) alternative was developed, which utilizes the SIP-R concept while  drastically reducing experimental duration. By integrating a technique known as the Flip-Flop  method in spin-lattice relaxation measurements into the SIP-R methodology, RAPTOR achieves  T₁ measurements in under five minutes without compromising accuracy or reliability.  collectively, the innovations described in this dissertation establish a significant step forward in NMR relaxometry, providing a versatile, efficient, and precise framework for T₁ measurements  across a wide range of molecular systems and environments.