dn_signal_decay

Signal Decay Information

Aside from acquisition and processing information, lineshapes are determined by how the signal decays. Typically, one chooses either Lorentzian (exponential decay), or Gaussian (Gaussian decay) lineshapes. However, advanced options allow adding a fixed amount of Lorentzian or Gaussian character, or a fixed mixture or Lorentzian and Gaussian decay.

dX.Broad: ‘dX.Broad’ is a string, specifying the type of decay which is varied during the fitting. This is set to ‘lorentz’, ‘gauss’, or ‘mixXX’. The first two options correspond to pure Lorentzian or Gaussian decay, respectively. ‘mixXX’ gives a fixed mixture of Gaussian and Lorentzian and decay, such that the fraction of Gaussian linewidth is XX/100 and the fraction of Lorentzian linewidth is 1–XX/100 (any number of digits may be used, so that the fraction is given by 0.XX…).

dX.gauss0: If ‘dX.gauss0’ is specified, a fixed amount of Gaussian broadening (in ppm) is added to all lineshapes. The output linewidth ('fit.lwX') does not include the fixed amount of Gaussian broadening, although the FWHM of each output peak ('fit.FWHMX') must include all contributions to the linewidth.

dX.lorentz0: If ‘dX.lorentz0’ is specified, a fixed amount of Lorentzian broadening (in ppm) is added to all lineshapes. As with ‘dX.gauss0’, the output linewidth ('fit.lwX') does not include this fixed amount of Lorentzian broadening, but it is included in the FWHM ('fit.FWHMX').