Gas-phase biomolecules: Structural motifs by laser spectroscopies combined with quantum computations

by Mr. Itai Kallos

Ben-Gurion University Of The Negev
at Quantum optics seminar

Wed, 13 Nov 2019, 15:00
Sacta-Rashi Building for Physics (54), room 207

Abstract

Student Seminar (Adviser: Ilana Bar)
A compact laser desorption source for spectroscopic studies of jet-cooled biomolecules, comprising simple parts for sample movement and desorption was designed, assembled and attached to a home-built time-off light mass spectrometer. Samples were prepared by mixing sample particles with graphite and pressing them as a thin layer into a graphite sample bar, positioned in front of a pulsed valve delivering the carrier gas. Continuous linear translation of the sample, in front of a fiber-coupled Nd:YAG laser beam (1064 nm, 10 Hz), led to its desorption, forming a stripe. The desorbed sample and carrier gas were expanded, skimmed, and entrained into the detection chamber. By assessing the relative timings between valve opening, desorption and ionizing lasers, with the optimal conditions for sample preparation, sample bar height, and movement velocity, optimization tests were conducted to improve signal stability and signal-to-noise ratio. The performance of the system was validated by monitoring the resonantly enhanced two-photon ionization and ionization-loss stimulated Raman spectroscopy spectrum of tryptamine and guanine, in the region of the origin band transitions. This spectrum resembled that previously acquired, from heated samples and quantum chemical calculation.

Created on 10-11-2019 by Folman, Ron (folman)
Updaded on 10-11-2019 by Folman, Ron (folman)