Year: 2023
Type: article
Abstract: We report femtosecond time-resolved measurements of the McLafferty rearrangement following the strong-field tunnel ionization of 2-pentanone, 4-methyl-2-pentanone, and 4,4-dimethyl-2-pentanone. The pump–probe-dependent yields of the McLafferty product ion are fit to a biexponential function with fast (∼100 fs) and slow (∼10 ps) time constants, the latter of which is faster for the latter two compounds. Following nearly instantaneous ionization, the fast time scale is associated with rotation of the molecule to a six-membered cyclic intermediate that facilitates transfer of the γ-hydrogen, while the ∼50–100 times longer time scale is associated with a π-bond rearrangement and bond cleavage between the α- and β-carbons to produce the enol cation. These experimental measurements are supported by ab initio molecular dynamics trajectories, which further confirm the time scale of this important stepwise reaction in mass spectrometry.
Authors: Jacob Stamm, Sung Kwon, Shawn Sandhu, Moaid Shaik, Rituparna Das, Jesse Sandhu, Bradley Curenton, Clayton Wicka, Benjamin G. Levine, Liangliang Sun, Marcos Dantus
Institutions: Michigan State University, Stony Brook University
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G1939119518, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4459110168, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), First Principles Simulation Methods for Strong Field Dynamics, Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5366236523, REU Site: CAS: Cross Disciplinary Training in Sustainable Chemistry and Chemical Processes, G7659349743, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI
OpenAlex ID: W4388212699