Sarah Arradondo

    Assistant Professor of Chemistry


    • Bachelor of Science: Chemistry (2014) Winona State University: Winona, MN

    • Doctor of Philosophy: Physical Chemistry (2019) University of Mississippi: University, MS


    My love for teaching and mentoring began in high school. I would always motivate my fellow classmates and community members to reach high to achieve their dreams. This idea of helping others grew in my mind, while I was learning that chemistry, physics and mathematics were the most exciting subjects ever. So, when I finally graduated from Winona State University, I knew that I wanted to become a physical chemistry professor at a small college. I wanted to be able to support and motivate young adults into pursuing their dreams. During my time at Washington College, I have learned that this is exactly where I am meant to be.

    I teach courses that are centered around applied algebra and calculus, including:

    • CHE 220: Quantitative Chemical Analysis
    • CHE 305: Thermodynamics, Statistical Thermodynamics and Kinetics
    • CHE 306: Quantum Chemistry and Spectroscopy


    The Arradondo lab characterizes non-covalent interactions within interesting systems using computational chemistry. Computational chemistry utilizes simulations to predict and model different chemical and physical properties within various systems.  We are currently focused on investigating room temperature ionic liquids and small molecule solvation with ab initio methods and density functionals in conjugation with large, robust basis sets. We also plan on collaborating with experimental scientists through a diverse range of topics including, atmospheric chemistry, material science and spectroscopy.

    The research lab is located at S204, which is an office space that includes eight desktop workstations that each have 32 GB of memory and Intel i5 hexa-core processors. These computers are currently available for connections to remote computational resources, but will soon be set up to run computations as well. All undergraduate researchers have access to the super computers maintained by the MERCURY consortium (Molecular Education and Research Consortium in Undergraduate computational chemistRY).

    Research Opportunities for Students 

    I am always looking for new students to join my lab for summer and semester research. Students interested in chemistry, physics, mathematics and computer science are encouraged to apply.  My research utilizes elementary calculus, Linux, and Python. No specific courses are required to participate in my research group, as you will be trained in navigating a Linux operating system, computational chemistry and basic programming. 

    Please email me if you are interested in joining my lab or learning more about computational chemistry. 


    • S. N. Johnson, T. L. Ellington, D. T. Ngo, J. L. Nevarez, N. Sparks, A. L. Rheingold, D. L. Watkins and G. S. Tschumper, CrystEngComm 21, 3151-3157 (2019). Probing Non-covalent Interactions Driving Molecular Assembly in Organo-electronic Building Blocks. (Cover Issue)
    • S. P. Lee, S. N. Johnson, T. L. Ellington, N. Mirsaleh-Kohan and G. S. Tschumper, ACS Omega. 3, 12936-12943 (2018). Energetics and Vibrational Signatures of Nucleobase Argyphilic Interactions.
    • S. N. Johnson, C. R. Hutchison, C. M. Williams, C. L. Hussey, G. S. Tschumper, and N. I. Hammer, J. Phys. Chem. C., 122, 27673-27680 (2018). Intermolecular Interactions and Vibrational Perturbations within Mixtures of 1-Ethyl-3-methylimidazolium Thiocyanate and Water. (Cover Issue)
    • S. N. Johnson and G.S. Tschumper, J. Comput. Chem., 39, 839-843 (2018). Hydrogen Bonding in the Mixed HF/HCl Dimer: Is It Better to Give or Receive? 
    • G. S. Tschumper, T.L. Ellington and S.N. JohnsonAnn. Rep. Comput. Chem.,13, 93-115 (2017). Dissociation in Binary Acid/Base Clusters: An Examination of Inconsistencies Introduced into the Many-Body Expansion by Naïve Fragmentation Schemes.

    Note: My maiden name is Johnson