Chemistry

Atmospheric Chemistry

Atmospheric spectroscopy of reactive and non-reactive trace gases in the atmosphere using infrared and Cavity Enhanced Spectroscopic Techniques.

 

Negative Ion Photoelectron Spectroscopy of Polycyclic Aromatic Hydrocarbon Anions

Negative Ion Photoelectron Spectroscopy of aromatic radical anions that are of interest to Astrochemistry, Environmental, and Biological systems. These studies have utilized high-level quantum chemical methods and Franck-Condon computations to obtain the vibrational spectra of neutral, medium-sized, polycyclic aromatic hydrocarbon radicals. New directions in this project involve the use of electroanalytical experimental methods to understand radical anions in the solution phase as well as the development of Velocity Map Ion Imaging technique.

Publications:

1. White, N. J.; Vargas, L. A.; Tunstall, W. W.; Koku Hannadige Abeysooriya, D. N.; Gichuhi, W. K., Cyanonaphthalene and cyanonaphthyl radicals: Vibrational structures via computed negative ion photoelectron spectra and thermochemistry of 1- and 2-cyanonaphthalene. J. Chem. Phys. 2024, 161 (3). https://doi.org/10.1063/5.0220823
2. Abeysooriya, D. N. K. H.;  White, N. J.;  Workman, K. T.;  Dupuy, J. A.; Gichuhi, W. K., Cyanocyclopentadiene-Annulated Polycyclic Aromatic Radical Anions: Predicted Negative Ion Photoelectron Spectra and Singlet-Triplet Energies of Cyanoindene and Cyanofluorene Radical Anions. J. Phys. Chem. A 2024. https://doi.org/10.1021/acs.jpca.3c08312
3. Workman, K. T.;  Usher, A. J.;  Henson, D. W.;  White, N. J.; Gichuhi, W. K., "Predicted Negative Ion Photoelectron Spectra of 1-, 2-, and 9-Cyanoanthracene Radical Anions and Computed Thermochemical Values of the Three Cyanoanthracene Isomers." J. Phys. Chem. 2023.Publication Date: April 28, 2023, https://doi.org/10.1021/acs.jpca.3c01178
4. Workman Kie, T.; Firth, Rebecca. A.; and Gichuhi W.K. “From Benzonitrile to Dicyanobenzenes: The Effect of an Additional CN Group on the Thermochemistry and Negative Ion Photoelectron Spectra of Dicyanobenzene Radical Anions’’ J. Phys. Chem. A 2023, 127, 1, 181–194. https://doi.org/10.1021/acs.jpca.2c07655
5. Gichuhi Wilson K, and Gamage Lahiru, P.; "Efficacy of the CO Tracer Technique in Partitioning Biogenic and Anthropogenic Atmospheric CO2 Signals in the Humid Subtropical Eastern Highland Rim City of Cookeville, Tennessee." Atmosphere 2023, 14(2), 208. https://doi.org/10.3390/atmos14020208
6. Firth, Rebecca. A.; Dimino, T. L.; Gichuhi, W. K., "Negative Ion Photoelectron Spectra of Deprotonated Benzonitrile Isomers via Computation of Franck–Condon Factors." J. Phys. Chem. A. 2022, 126, (29), 4781-4790. https://doi.org/10.1021/acs.jpca.2c03220
7. Gamage, Lahiru, P.; Hix, Elijah G.;and Gichuhi W.K. “Ground-Based Atmospheric Measurements of CO:CO2 Ratios in Eastern Highland Rim Using a CO Tracer Technique,” ACS Earth Space Chem. 2020, 4(4), 558–571. https://doi.org/10.1021/acsearthspacechem.9b00322
8. Gichuhi W.K. “Astrochemistry as a Gateway to Teaching and Learning Threshold Concepts in Physical Chemistry,” World Journal of Chemical Education. 2019, 7(3), 209–215. DOI: 10.12691/wjce-7-3-4
9. Gamage Lahiru P.; and Gichuhi W.K. “Efficacy of a Wavelength-Scanned Cavity Ring-Down Spectroscopic Technique in Estimating Enteric Methane Emissions in Ruminants,” ACS Earth Space Chem., 2018, 2(7), pp 673–68. https://doi.org/10.1021/acsearthspacechem.8b00023
10. Nelson, D.J, Gichuhi, W.K., Nichols, C.M., Bierbaum, V.M, Lineberger, W.C, and Lehman J.H. “Photoelectron Spectroscopy and Thermochemistry of o-, m-, and p-Methylenephenoxide Anions,” Phys. Chem. Chem. Phys., 20(39), 25203-25216, 2018. DOI: DOI: 10.1039/c8cp05403g
11. Nelson, D.J., Gichuhi, W.K., Miller, E., and Lineberger, W.C. “Anion Photoelectron Spectroscopy of Deprotonated ortho-, meta-, and para-Methylphenol,” Journal of Chemical Physics, 146(6), 074302, 2017. DOI: https://doi.org/10.1063/1.4975330
12. Gichuhi, W.K., and Suits, A.G. “Low-Temperature Branching Ratio for the Reaction of State-Prepared N2+ with Acetonitrile,” J. Phys. Chem A, 116(3), 938, 2012.
13. Gichuhi, W.K., and Suits, A.G. “Primary Branching Ratios for the Low Temperature Reaction of State-Prepared N2+ with CH4, C2H2 and C2H4,” J. Phys. Chem. A, 115(25), 7105, 2011.
14. Gichuhi, W.K., Mebel, A.M., and Suits, A.G. “UV Photodissociation of Ethylamine Cation: A Combined Experimental and Theoretical Investigation,” J. Phys. Chem. A 114, 51, 13296: cover for the December 30, 2010, 114,51 issue.
15. Suits, A.G., Gichuhi, W.K., and Mebel, A.M. General Discussion; Faraday Discuss. 146.
16. Suits, A.G., Gichuhi, W.K., Silva, R., Doyle, M.B., Mebel, A.M., and Kaiser, R.I. “Laboratory Studies of Primary Photochemistry Relevant to Titan’s Atmosphere,” LPI Contribution No. 1538, 5283.
17. Huang, C., Zhang, F., Kaiser, R.I., Kislov, V.V., Mebel, A.M., Silva, R., Gichuhi, W.K., and Suits, A.G. “Photodissociation of the Diacetylene Dimer and Implications for Hydrocarbon Growth in Titan’s Atmosphere,’’ Astrophysical Journal, 714, 1249, 2010.
18. Silva, R., Gichuhi, W.K., Kislov, V.V., Mebel, A.M., and Suits, A.G., “UV “Photodissociation of Cyanoacetylene: A Combined Ion Imaging and Theoretical Investigation,” J. Phys. Chem. A, 113(42), 11182–11186, 2009.
19. Silva, R., Gichuhi, W.K., Doyle, M.B., Winney, A.H., and Suits, A.G. “Photodissociation of Heptane Isomers and Relative Ionization Efficiencies of Butyl and Propyl Radicals at 157 nm,” Phys. Chem. Chem. Phys., 11, 4777-4781, 2009.
20. Silva, R., Gichuhi, W.K., Huang, C., Doyle, M.B., Kislov, V.V., and Mebel, A.M., and Suits, A.G. “H-elimination and Metastable Lifetimes in the UV Photoexcitation of Diacetylene,”Proc. Nat. Acad. Sci, 105, 12713-12718, 2008.

 

 

 

 

 

• CHEM 3510 – Physical Chemistry I (Quantum Chemistry, Spectroscopy, and Intro. to Statistical Mechanics)
• CHEM 3520 – Physical Chemistry II (Classical and Statistical Thermodynamics, Chemical Kinetics and Dynamics)
• CHEM 3520 and CHEM 3520 P-Chem Labs Instructor and Coordinator
• CHEM 6320 – Advanced Physical Chemistry (Advanced Chemical Kinetics and Dynamics, Statistical Mechanics, and Modern Experimental Techniques in Physical Chemistry)
• CHEM 5970- Special Topics in Quantum Chemistry
• CHEM 4970 – Special Topics: Introduction to Astrochemistry
• CHEM 3500- Elements of Physical Chemistry (A One Semester Overview of Physical Chemistry)
• CHEM 6970 – Advanced Special Topics (Astrochemistry)
• EVSC 7990 – Advanced Special Topics in Atmospheric Chemistry and Astrochemistry
• CHEM 1120- General Chemistry II

Research Opportunities:

The Gichuhi Research Group is currently accepting students for the 2023-24 academic year. Interested students should contact Dr. Gichuhi (wgichuhi@tntech.edu) for additional information.

Summer 2024 Undergraduate Research Grant