PhaseShiftSpectra[spectra,phi₀]

aplies the 0th order phase phi0 to the spectra.

PhaseShiftSpectra[spectra,ppm,gyro,phi₁]

aplies the 1st order phase phi1 to the spectra. The ppm can be obtained using GetPpmRange and gyro with GetGyro.

PhaseShiftSpectra[spec,ppm,gyro,{phi₀,phi₁}]

aplies the 0th and 1st order phases {{phi0phi0, phi1} to the spectra. The ppm can be obtained using GetPpmRange and gyro with GetGyro. The 0th order phase phi0 is in radians and the 1st order phase phi1 is in ms.