Our Research

When molecules interact noncovalently through hydrogen bonding or other electrostatic interactions, pi-pi interactions, or Van der Waals forces, their physical properties change. We study the physical properties of interacting molecules in environments ranging from the single molecule to the bulk using different laser-based spectroscopic methods and computational modeling. Our spectroscopic capabilities include high resolution Raman spectroscopy, the study of size-selected clusters in the gas phase, the use of single molecule techniques such as surface enhanced Raman spectroscopy, and other laser-based spectroscopies to study interacting molecular architectures. These include excited state lifetime, time correlated single photon counting (TCSPC) studies, ns, ps, and fs transient absorption spectroscopy (UltrafastSystems), and quantum yield determinations. Such studies help answer long-standing questions involving the effects of intermolecular interactions on biologically relevant systems and also in developing devices such as solar cells that incorporate conjugated organic molecules. Both as team members and individually, we work to make new strides in the overall understanding of how molecules interact with each other and how their structure affects their resulting properties. The Hammer Research Group also works to develop new resources and programming for chemical education.


Funded Grants

“REU Site: Ole Miss Physical Chemistry Summer Research Program” (PI)

    National Science Foundation (CHE-2150352), September 2022 - August 2025

“Photoinduced Interfacial Charge Transfers with Organic Sensitizers using Low Energy Photons and Fundamental Physical Organic Design Concepts” (co-PI)

    National Science Foundation (CHE-1954922), September 2020 - August 2023

“Center for Emergent Molecular Optoelectronics (CEMOs)” (Senior Personnel)

    National Science Foundation EPSCoR (OIA-1757220), October 2018 - September 2023

“REU Site: Ole Miss Physical Chemistry Summer Research Program” (PI)

    National Science Foundation (CHE-1757888), September 2018 - August 2022

“RII Track-2 FEC: Feeding and Powering the World - Capturing Sunlight to Split Water and Generate Fertilizer and Fuels” (PI)

    National Science Foundation EPSCoR (OIA-1539035), August 2015 - July 2020

“MRI: Acquisition of a Raman Spectrometer for Research and Training at the University of Mississippi” (PI)

    National Science Foundation (CHE-1532079), September 2015 - August 2018

“REU Site: Ole Miss Physical Chemistry Summer Research Program” (PI)

    National Science Foundation (CHE-1460568), September 2015 - August 2018

“CAREER: Spectroscopically Tracking the Evolution of Noncovalent Interactions from the Single Molecule Level to the Condensed Phases” (PI)

    National Science Foundation Faculty Early Career Development (CAREER) Program (CHE-0955550), March 2010 - February 2017

“Modeling and Simulation of Complex Systems” (Senior Personnel)

    National Science Foundation EPSCoR (EPS-0903787), September 2009 - August 2016

REU Site: Ole Miss Physical Chemistry Summer Research Program (PI)

    National Science Foundation (CHE-1156713), September 2012 - August 2016

“Dynamics of Strand-Crossover Formation in Cadherin” (Co-PI)

    National Science Foundation (MCB-0950494), July 2010 - June 2014



Our molecular spectroscopy laboratory on the campus of the University of Mississippi in scenic Oxford, MS serves as a resource center for the South.

Transient Absorption Spectroscopy: We feature a $1 million femtosecond transient absorption and excited state fluorescence spectroscopy system. This system includes a Coherent Astrella fs pump laser and OPAs capable of producing ultraviolet to mid-infrared fs pulses and two Ultrafast Systems transient absorption spectrometers (Helios Fire and Helios-IR). We also utlize a Edinburgh Instruments ns Laser Flash Photolysis spectrometer.

Fluorescence Spectroscopy: Our laboratory studies diffuse reflectance and fluorescence emission, lifetimes, and efficiencies from single molecules, solutions, solids, and other environments from the ultraviolet to the infrared.

Raman Spectroscopy: We specialize in high resolution and low energy Raman spectroscopy of interacting hydrogen bonded complexes and important materials.