This is NYSBC standard data set and pulse program for CNC experiment with 2 double cross polarization steps. The pulse program has power safety limitations specific for the particular probe. The pulse program dbcp13C_2D_3.2EF750.nysbc, ramp shape file tancn_100_SCALE and include file power_intro.incl are located in the dataset directory.
Cross Polarization in the tilted frame: assignment and spectral simplification in heteronuclear spin systems, Marc Baldus, Aneta Petkova, Judith Herzfeld, Robert Griffin, Journal of Molecular Physics, 1998, 95 (6) p.1197-1207 https://www.tandfonline.com/doi/abs/10.1080/00268979809483251
To minimized heating of conductive samples, we recommend using an Efree/lowE probe. However, a combination of frictional heating from spinning and RF heating on long pulses on both channel may cause substantial sample heating and temperature gradient across the sample even in an Efree probe. The heating may damage the sample. The heating and temperature gradient across the rotor may substantially compromise the precision of measurements and data fitting.
https://www.ncbi.nlm.nih.gov/pubmed/10868566?dopt=Abstract Heating of samples induced by fast magic-angle spinning, Brus, J., Solid State Nucl. Magn. Reson. 16, 151–160 (2000).
https://onlinelibrary.wiley.com/doi/abs/10.1002/mrc.4450 Heating and temperature gradients of lipid bilayer samples induced by RF irradiation in MAS solid-state NMR experiments, Wang, J., Zhang, Z., Zhao, W., Wang, L. & Yang, J., Magn. Reson. Chem. 54, 753–759 (2016).
https://www.biorxiv.org/content/10.1101/566729v1.full TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments Dongyu Zhang, Boris Itin, Ann E. McDermott; preprinted TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments Dongyu Zhang, Boris Itin, Ann E. McDermott; preprinted
DCP experiments require long simultaneous medium to high power pulses on 1 three channels simultaneously. Adjust the probe power length and safety limitations in the pulse sequence to follow your probe specifications. When in doubt, contact the manufacturer.
DCP experiment is very sensitive to Hartmann Hahn matching conditions (<0.5W) and to field offsets (20-40ppm). It is, effectively, a band selective experiment. DCP matching conditions may change as a probe detunes. DCP efficiency both decreases and becomes more sensitive to Hartmann Hahn matching conditions at higher spinning frequencies. With typical Bruker probe power limitations, the most efficient DCP condition is 2.5 /1.5 (rotor spinning frequncy) 13C/15N at the lower spinning frequencies and 2.5/1.5 15N/13C at the higher spinning frequencies.
The experiments were performed with crystallized u-15N,13C-labeled-N-acetyl-valine and u-15N,13C membrane protein in hydrated lipids.