Femtosecond pulse shaping as analytic tool in mass spectrometry of complex polyatomic systems

Abstract

An additional dimension to mass spectrometric studies on building blocks of proteins is discussed in this paper. The present approach is based on tailored femtosecond laser pulses, using the concept of strong-field pulse shaping in an adaptive feedback loop. We show that control strategies making use of coherent properties of the electromagnetic wave allow one to break pre-selected backbone bonds in amino acid complexes that may be regarded as peptide model systems. Studies on different chromophores, such as phenylalanine and alanine, while keeping the backbone structure unchanged elucidates the effect of the excitation dynamics on the relaxation pathways. The observation of protonated species in the corresponding mass spectra indicates that optimal control of ultrafast laser pulses may even be useful to study intramolecular reactions such as hydrogen- or proton-transfer in particular cases. This opens new perspectives for biophysical and biochemical research, since these photochemical reactions are suggested to explain, e.g. photostability of DNA.

Fragmentation of Neutral Amino Acids and Small Peptides by Intense, Femtosecond Laser Pulses

“…This can be used to stimulate particular quantum pathways in complex molecules and the production of specific fragments can be optimized with pulse feedback control loops [11].…”

Time-resolved studies of ultrafast wavepacket dynamics in hydrogen molecules

“…Spectral pulse shaping techniques are currently providing experimentalists with an adaptive tool [118,119] for targeting the cleavage of specific chemical bonds (e.g. in amino acids [120]) and shorter pulse durations may even enable ultrafast electron transport processes to be studied [121]. This builds on the existing application of femtosecond lasers in gas-phase chemistry [122] and other pump-probe spectroscopy studies [123].…”

Ultrafast thermalization characteristics in Au film irradiated by temporally shaped femtosecond laser pulses

“…Many potential applications emerged due to progress made in the pulse shaping techniques, such as the optimal control of chemical reaction [9], the enhanced ionization process [10] and the mass spectrometry analysis [11]. More recently, it is found that temporally shaped pulses train excitation enables new opportunities for optimal processing of materials [12].…”