In 1968, Jameson returned to University of Illinois at Chicago as an assistant professor. She was made full Professor in 1976. Jameson spent time as a visiting scientist at the University of Cambridge, University of Oxford and Queen's University. Her work uses quantum chemistry and molecular dynamics to understand molecular electronic properties such as nuclear magnetic shielding. Jameson worked on NMR in the gas and liquid phase to establish inter and intra-molecular effects on NMR parameters. She looked at how isotopic substitution impacted the chemical shift of NMR, and used rotational–vibrational averaging theory to explain intramolecular effects, such as isotope effects and the temperature dependence of shifts in NMR. She used gas phase NMR to extract relaxation times that allowed calculation of effective collision cross-sections. She described how NMR shifts could be used as a paradigm for electronic properties of molecules.
Jameson established the field of Xe NMR to study local environments with high sensitivity and fast data acquisition. She used Xe and grand canonical Monte Carlo simulations to study adsorption and diffusion in zeolites. She provided the mathematical explanation for the chemical shift and spin-spin coupling observed in NMR spectroscopy of chiral materials. She contributed to the book Multinuclear NMR, which provided information about the theory and observations in nuclear magnetic resonance spectroscopy of various nuclei. She was the first woman to deliver NMR section Rocky Mountain Conference on Analytical Chemistry Vaughan Lecture in 2000. She spent a year as a Visiting Miller Professor at the University of California, Berkeley. In 2008 Jameson returned to the Philippines to teach a quantum chemistry course for university teachers. She is a member of the Philippine-American Academy of Science and Engineering.