Transmission Spectrometer

Although the absolute sensitivity of this 24-660 GHz transmission device is lower than that of the quasi-optical system, samples for the transmission apparatus may be very large (0.5 mL and above), thus offsetting the sensitivity disadvantage. The instrument is coupled to a 15/17 T superconducting magnet.

Samples are also substantially larger than in Bruker W-Band, so that spectra are often better than those obtained on the Bruker machine if enough sample is available. Thin Teflon vessels with an outer diameter of up to 9 mm and a depth of up ca. 10 mm are used as sample containers. Standard X-Band 3 mm and 4 mm quartz tubes can also be used for samples requiring sealing. Gelatin capsules up to the size ‘00’ (8 mm diameter) as well as polyethylene vials were also successfully employed. The sample temperature can be controlled over the range of 3K to 309K.

The samples are most often powders or frozen solutions in organic solvents or in water. Single crystals can be measured, but no crystal rotator is available.

The instrument does not employ resonance cavity. The superconducting magnet has been factory-calibrated, but for accurate measurements usage of g standards is recommended (for example DPPH or phosphorus doped into silicon).

Transition metal complexes, some compounds of the f-electron metals (gadolinium) as well as organic radicals have been studied on this spectrometer. The sensitivity is sufficient for studies on some enzymes (the manganese-containing oxalate decarboxylase, for example).

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See panoramic view of this magnet.

Details

  • Specs

  • Compatible Techniques

  • Available Equipment

  • Sample Types

  • Frequency: 24 – 660 GHz
  • Field Strength: 15/17 tesla
  • Bore Diameter: 61 mm
  • Homogeneity: 20 ppm
  • Number of input and output leads possible: 2
  • Temperature: 3 K – 309 K
  • Crystal Rotation: No
  • Pressure: Ambient
  • Sensitivity: Absolute: 1013 spin/mT, concentration: 5·1013 spin/(cm3·mT)
  • Sample Size: 5-300 mg (powder), 0.2-1 mL (solution)
  • Optical Excitation: Yes
  • Open for users who would pay for magnet time: Yes
  • The microwave source of this instrument can be also used with the resistive magnets of the DC facility
  • The BWO microwave source can be used with this instrument
  • Air-sensitive or reactive sample
  • Frozen solutions, including aqueous
  • Powders & polycrystals
  • Single crystal
  • Thin films

Images & Sample Data

Click on images for details.

View the embedded image gallery online at:
https://nationalmaglab.org/user-facilities/emr/instruments-emr/transmission#sigProId202af45cd3

Related Publications

Stoll, S., et al, Hydrogen bonding of tryptophan radicals revealed by EPR at 700 GHz, J. Am. Chem. Soc., 133 (2011) Read online 

Tran, B.L., et al, Reactivity studies of a masked three-coordinate vanadium(II) complex, Angew. Chem. Int. Ed., 49 (2010) Read online 

Krzystek, J., et al, Cobalt(II) “scorpionate” complexes as models for cobalt-substituted zinc enzymes: Electronic structure investigation by high-frequency and -field Electron Paramagnetic Resonance spectroscopy, J. Am. Chem. Soc., 132 (2010) Read online 

Ozarowski, A., et al, High-Field EPR and Magnetic Susceptibility Studies on Binuclear and Tetranuclear Copper Trifluoroacetate Complexes. X-ray Structure Determination of Three Tetranuclear Quinoline Adducts of Copper(II) Trifluoroacetate, J. Am. Chem. Soc., 131 (2009) Read online 

Ozarowski, A., et al, High-Frequency and -Field EPR of a Pseudo-octahedral Complex of High-Spin Fe(II): Bis(2,2'-bi-2-thiazoline)bis(isothiocyanato)iron(II), J. Am. Chem. Soc., 126 (2004) Read online 

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Last modified on 21 June 2021
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