We use matrix-isolation spectroscopy to trap reactive species, weakly bound complexes, and small neutral molecules at cryogenic temperatures. This technique enables us to stabilize short-lived species and study their conformational preferences, intermolecular interactions, and vibrational signatures in detail.
Figure 1. 3D rendering of the matrix-isolation instrument design.
We have shown that the deposition dynamics and matrix composition can play a direct role in shaping molecular behavior. For example, we discovered that matrix gas identity and deposition angle can alter the conformer distribution of methyl nitrite (CH3ONO), challenging long-standing assumptions about passive trapping in low-temperature matrices. We also reported the formation of a [(HCN)3·CH3Cl] complex—highlighting the ability of cryogenic environments to stabilize prebiotic motifs through weak interactions.
Figure 2. Laboratory spectra showing the conformer dependence of matrix-isolated molecules, and the computational treatment needed to interpret spectra.
Ongoing work in our group extends this approach to quantum-state-resolved studies of small homonuclear molecules such as H2. Even though H2 lacks a permanent dipole moment and is infrared-inactive in the gas phase, the perturbative effect of the surrounding matrix lattice enables direct detection of dilute H2 populations and their nuclear-spin isomers. These measurements allow us to probe state distributions and ortho–para conversion in confined, cryogenic environments.
Figure 3. The matrix-isolation instrument in the lab, configured for cryogenic spectroscopy.
Selected Publications
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Hockey, E. K., et al. “Matrix-formation dynamics dictate methyl nitrite conformer abundance,”
J. Chem. Phys., 2024, 160, 094303.
DOI: 10.1063/5.0188433 -
Hockey, E. K., et al. “Weakly bound complex formation between HCN and CH3Cl: A matrix-isolation and computational study,”
J. Phys. Chem. A, 2022, 126, 3110–3123.
DOI: 10.1021/acs.jpca.2c00716