EQuAL Student Seminar: Sam Kresch

Inelastic Recoil Spectroscopy: Rotationally Resolved Spectroscopy of a Single Molecule

Inelastic Recoil Spectroscopy (IRS) is a single-molecule action spectroscopy method that enables mid-infrared vibrational spectra of individual trapped molecular ions. By monitoring recoil events that occur when an excited molecule undergoes inelastic collisions with a cold buffer gas, IRS translates photon absorption into a measurable motional signature without destroying the ion. This approach overcomes the averaging intrinsic to ensemble spectroscopy, revealing vibrational and rotational structure one molecule at a time. IRS offers a powerful platform for molecular identification, studies of rare or reactive species, tests of fundamental physics, and progress towards quantum control of polyatomic molecules.