Steric Effect in Threshold Photoionization Dissociations of Serine Conformers

TL;DR

This study investigates how steric effects influence the threshold photoionization dissociations of serine conformers using advanced ab initio calculations and innovative mass spectrometry techniques, revealing selective bond breaking and dynamic processes.

Contribution

It introduces a combined computational and experimental approach to elucidate steric effects in serine dissociation at threshold ionization energies.

Findings

Selective bond cleavage at ionization thresholds.

Identification of proton transfer and reorientation processes.

Differentiation of fragment pathways based on conformers.

Abstract

Steric effect in the threshold dissociative ionizations of serine conformers [CH2OH-C\alphaH(NH2)-C\betaOOH] is revealed by high-level ab initio calculations combined with our newly developed infrared laser desorption / tunable VUV photoionization mass spectrometry. We find that near the ionization thresholds the C\alpha-C\beta and C\alpha-C bonds are selectively broken for the respective cationic conformers, yielding the different fragments. Novel dynamic processes, proton transfer and reorientation between the predissociative fragments, are involved in the threshold photoionization dissociations.