Contact

Wodtke_Portrait.jpg
Alec M. Wodtke
Director, Professor at the University of Göttingen
Phone:+49 551 201-1261Fax:+49 551 201-1501

Curriculum Vitae

Department of Dynamics at Surfaces

Facilities

The department is outfitted with a variety of sophisticated instruments for experimental study of dynamics at surfaces, many of which are custom designed and unique in the world. These include the following.

<strong></strong>The narrowband output of a cw ring dye laser (above) is pulse amplified and converted to IR using Differ-ence Frequency Generation, then amplified using Optical Parametric Amplification. This unique light source produces more than 30 mJ/pulse in the near IR with a bandwidth of 120 MHz. It is ideal for overtone pumping of small molecules for use in state-to-state beam-surface scattering experiments. Zoom Image
The narrowband output of a cw ring dye laser (above) is pulse amplified and converted to IR using Differ-ence Frequency Generation, then amplified using Optical Parametric Amplification. This unique light source produces more than 30 mJ/pulse in the near IR with a bandwidth of 120 MHz. It is ideal for overtone pumping of small molecules for use in state-to-state beam-surface scattering experiments. [less]
  • A Beam-surface scattering instrument for state-to-state inelastic scattering ("Beamer-I") with high-power narrow-band infrared laser system for overtone pumping. This instrument was built in Santa Barbara and moved to Göttingen. The laser systems were refurbished and a new and extraordinary laser system was installed for use with this machine. That laser employees a pulse amplified continuous wave ring dye laser with difference frequency generation and optical parametric amplification. Pulse energies of 30 mJ with 120 MHz line-widths between 1.8 and 2.5 µm are presently used for overtone excitation in NO and CO. State-to-state scattering is carried out using REMPI detection.

  • A Beam-surface scattering instrument for quantum state prepared and oriented molecules ("Orientation machine") with specialized Fourier transform limited pulsed UV lasers for Stimulated emission pumping and Stimulated Raman Rapid Adiabatic Passage optical pumping. This instrument was built in Santa Barbara and moved to Göttingen. All laser systems were refurbished and two home-made OPO’s were built and installed for generation of UV radiation at 206 nm (and other wavelengths) to serve as the PUMP pulse in PUMP DUMP preparation of highly vibrationally excited NO and CO. The instrument is equipped with special electrodes for orientation of molecular beams using a new approach developed in our lab: Optical state selection with adiabatic orientation.
  • A Stark-decelerator surface-scattering apparatus ("Stark machine") combines Stark manipulation of molecular beams with ultrahigh vacuum surface scattering. The project is in collaboration with Gerard Meijer’s group at the FHI in Berlin.
  • A PC Cluster implements the Vienna ab initio Software Package (VASP) for DFT calculations of electronically-adiabatic, ground-state potential energies of atoms and molecules interacting with surfaces. Both classical and quantum versions of the Independent Electron Surface Hopping (IESH) theory developed by Shenvi and Tully are also operational on our cluster.
  • An ultrafast spectroscopy lab is part of the department. This includes laser facilities allowing for UV, VIS and IR spectroscopic measurements in the femto- to nanosecond time range. fs light sources are based on Ti:Sapphire oscillator/regenerative amplifier technology. A variety of subsequent frequency conversion units are employed including broadly tunable OPA’s.
<strong></strong>The nanolab is presently producing cm2 sam-ples of high quality graphene. (a) Raman spectra for transferred graphene on SiO<sub>2</sub> (250 nm)/Si(100) substrate. The inset is the optical microscope images of the graphene. (b) TEM and diffraction pattern images of one monolayer graphene on lacey carbon covered Cu grid. Zoom Image
The nanolab is presently producing cm2 sam-ples of high quality graphene. (a) Raman spectra for transferred graphene on SiO2 (250 nm)/Si(100) substrate. The inset is the optical microscope images of the graphene. (b) TEM and diffraction pattern images of one monolayer graphene on lacey carbon covered Cu grid. [less]
  • A nanoscience synthesis lab (nanolab) has been outfitted for production of novel sur-faces for future investigations aimed at controlling the molecule surface interactions. A computer controlled CVD tube furnace and a Zeiss optical microscope are work horses here.
 
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