Research
Our research group is exploring the development and use of coherent multidimensional spectroscopy to address persistent severe congestion and disorganization problems normally observed in the electronic (UV-visible) spectroscopy of many gas phase molecules. We are interested in applying this newly developed technique on molecules that have atmospheric relevance.
Current Projects
High Resolution Coherent 2D spectroscopy
High Resolution Coherent 2D spectroscopy can be used to analyze molecules that are too difficult to analyze using other high resolution spectroscopic techniques. The peaks are spread out along two dimensions in patterns that are easily recognizable. Within these patterns, peaks are automatically sorted by quantum number and species. Spectral resolution is improved and congestion is reduced using this approach. These capabilities have been demonstrated using simple diatomic molecules. We are currently exploring how to achieve these capabilities when applied to more complicated polyatomic molecules, including those with conical intersections and those that are floppy.
High Resolution Coherent 3D spectroscopy
High Resolution Coherent 3D spectroscopy is useful when Coherent 2D spectra are still too congested and/or when peaks are not clearly resolved. Unlike coherent 2D spectroscopy, coherent 3D spectroscopy can provide selectivity. Selectivity by species or by energy level can be achieved by fixing one of the three frequencies and scanning the other two. The resulting spectrum should contain only selected peaks, based upon the levels and species selected by the fixed frequency.
Current efforts are under way to develop new and more powerful 3D methods and strategies, including smart approaches that can reduce the amount of data acquisition time required when expanding from two dimensions to three. The figure to the left illustrates how perpendicular 2D slices through 3D space can be used to reduce the amount of data needed to generate and analyze 3D spectra. |
High Resolution 2DIR Spectroscopy
Simulated 2DIR spectrum of methane.
2DIR spectroscopy is a relatively new technique that can record two-dimensional IR spectra in a way that is similar to 2D NMR. It can be used to overcome many problems that are insurmountable when using conventional 1D infrared spectroscopy (e.g., when the sample is a mixture).
We have recently built and tested the very first high resolution 2DIR system for use on gas samples. The resulting spectra show patterns that have the shape of an asterisk.
We have recently built and tested the very first high resolution 2DIR system for use on gas samples. The resulting spectra show patterns that have the shape of an asterisk.
This material is based on work supported by the National Science Foundation under Grants CHE-1608010, CHE-1832098, and CHE-1832098.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF)
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF)