Sm 4000 8t magnetocryostat

MCD and low-temperature Abs spectra were collected on a Jasco J-715 spectropolarimeter in conjunction with an Oxford Instruments SM-4000 8T magnetocryostat. All MCD spectra presented herein were obtained by taking the difference between spectra collected with the magnetic field oriented parallel and antiparallel to the light propagation axis to remove contributions from the natural CD and glass strain. X-band EPR spectra were obtained by using a Bruker ESP 300E spectrometer in conjunction with an Oxford ESR 900 continuous-flow liquid helium cryostat and an Oxford ITC4 temperature controller. The microwave frequency was measured with a Varian EIP model 625A CW frequency counter. All spectra were collected using a modulation amplitude of 10 G and a modulation frequency of 100 kHz. EPR spectral simulations were performed using Dr. Mark Nilges’s SIMPOW program.⁴⁴

LT MCD spectra were collected with a Jasco J-715 spectropolarimeter in conjunction with an Oxford Instruments SM4000-8T magnetocryostat. MCD spectra are presented as the difference between spectra obtained with the magnetic field aligned parallel and antiparallel to the light propagation axis to eliminate contributions from the CD background and glass strain. For Cys-bound ADO, variable temperature, variable field (VTVH) MCD data were collected by measuring the signal intensity as a function of magnetic field at a constant wavelength (477 nm = 20.964 cm⁻¹) for several fixed temperatures. The data were fitted with the S=1/2 Brillouin function³⁵ $$B_{{}^1∕_2}(x)=\tanh (x)$$
where $\mathrm{x}=\frac{{\mathrm{u}}_{\mathrm{J}}\mathrm{H}}{{\mathrm{k}}_{\mathrm{B}}\mathrm{T}}$ , μ_j is the Bohr magneton, H is the field (in Tesla), k_B is the Boltzmann constant, and T is the temperature.
X-band EPR data were collected using a Bruker ELEXSYS E500 spectrometer. The sample temperature was maintained at 20 K by an Oxford ESR 900 continuous flow liquid He cryostat regulated by an Oxford ITC-503S temperature controller. All spectra were obtained using the following experimental parameters: frequency = 9.386 GHz; microwave power = 12.62 mW; modulation amplitude = 3 G; modulation frequency = 100 kHz. The program EasySpin (version 5.2.25) was used to fit the experimental EPR spectra.^{36 (link)}

Low-temperature Abs and MCD spectra were collected on a Jasco J-715 spectropolarimeter in conjunction with an Oxford Instruments SM-4000 8T magnetocryostat. All reported MCD spectra were obtained by taking the difference between spectra collected with the magnetic field oriented parallel and antiparallel to the light propagation axis to remove contributions from the natural CD and glass strain. If appropriate, the temperature-independent contributions to a given MCD spectrum were removed by subtracting the spectrum obtained at 25 K from the low-temperature spectrum.
Variable-temperature variable-field (VTVH)-MCD data were obtained at three different wavelengths corresponding to the peak positions of the most intense features in the MCD spectrum of EutT^WT/Co. The experimental data were fit as described elsewhere.²⁸ X-band EPR spectra were obtained by using a Bruker ESP 300E spectrometer in conjunction with an Oxford ESR 900 continuous-flow liquid helium cryostat and an Oxford ITC4 temperature controller. The microwave frequency was measured with a Varian EIP model 625A CW frequency counter. All spectra were collected using a modulation amplitude of 10 G and a modulation frequency of 100 kHz. EPR spectral simulations were performed using the SIMPOW6 program.²⁹