Amplified Ti:Sa pulses produce broadly tunable (200-2500nm) fs pulses via optical parametric amplification (OPA). Harmonic generation and sum frequency mixing of the OPA output provides the desired wavelengths for the pump process, whereas 4th harmonic generation of the Ti:Sa fundamental supplies a 200nm probe photon.
 
Text Box: Click on image for a larger versionRounded Rectangle: Femtosecond/picosecond laser system: Link to Coherent ultrafast lasers … Verdi, Mira, Evolution, Legend, Opera

High temperature glass nozzle

 

•        glass tube, vespel plug with small orifice, no metal surface

•        sample applied to glass wool
ฎ increased surface area

•        setup heated with cartridge heaters

•        expansion of sample and carrier gas

 
 

Laser desorption/ablation

 

•        sample (mixture) pressed as rod

•        rotating & translating rod irradiated with dithering laser focus
  ฎ sample desorbs/ablates

•        supersonic expansion of sample and carrier gas

 
 

The two time-delayed laser pulses interact with a skimmed molecular beam (sample vaporized by heating or laser ablation) in the ionization region of the PEPICO spectrometer. The photoelectron spectrometer uses a magnetic ‘bottle’ for high collection efficiency of photoelectrons and ion detection based on a Wiley-McLaren TOF mass spectrometer.
 
Rounded Rectangle: Molecular beam sources: Until now, only a few gas-phase spectroscopic studies have been dedicated to small biomolecular building blocks, reflecting the difficulty of vaporizing them in detectable quantities. Low volatility and thermal decomposition of many biomolecules, make it necessary to employ advanced molecular beam techniques. Rounded Rectangle: Magnetic bottle-type photoelectron photoion coincidence spectrometer: