Slightly shifted spectrum when using Osprey LCModel wrapper

[hmonsivais]

Hello @admin,

I have encountered a peculiar issue where, when I process unedited data in Osprey and use the LCModel wrapper to fit it, the spectrum appears slightly shifted to the right

. However, when I process the same file using the command line to run the LCModel on my MacBook Air (M3, Sequoia 15.6.1), I see no shift and everything aligns where it is supposed to be. I’m using the same control file written by Osprey, with the only change being the path to the basis file.

I vaguely recall reading that LCModel attempts to correct any shifts in the spectrum, so is this feature disabled in the LCModel wrapper in Osprey? Or, could the shift be in my basis set .mat file? I used the basis io_LCMBasis.m basis function in Osprey to make my basis file compatible with Osprey.

Any tips would be greatly appreciated!

Best,
Humberto

[admin]

Hi Humberto,

During loading/processing, Osprey makes some attempts to pre-phase and frequency-correct spectra - they’re intended to correct any coarse frequency/phase errors before feeding the spectrum into the modeling. But yeah, it seems like in this case it has actually moved the spectrum a little to the right.

LCModel accounts for small frequency shifts between basis set and data on its own accord (you’re right about that), so I don’t think this is too problematic.

Best,
Georg