_peak

This category stores peak-profile parameters used by powder diffraction and total-scattering calculations. The active peak-profile category is selected from the experiment:

experiment.peak.type = 'pseudo-voigt'

Constant-wavelength powder profiles

The constant-wavelength pseudo-Voigt profile uses Gaussian and Lorentzian broadening parameters:

_peak.broad_gauss_u
_peak.broad_gauss_v
_peak.broad_gauss_w
_peak.broad_lorentz_x
_peak.broad_lorentz_y

When empirical asymmetry is enabled, the profile also uses:

_peak.asym_p1
_peak.asym_p2
_peak.asym_p3
_peak.asym_p4

Time-of-flight powder profiles

The time-of-flight pseudo-Voigt profiles use instrument-dependent Gaussian broadening, back-to-back exponential rise and decay terms, and optionally Lorentzian broadening or double-exponential asymmetry terms:

_peak.gauss_sigma_0
_peak.gauss_sigma_1
_peak.gauss_sigma_2
_peak.rise_alpha_0
_peak.rise_alpha_1
_peak.decay_beta_0
_peak.decay_beta_1
_peak.lorentz_gamma_0
_peak.lorentz_gamma_1
_peak.lorentz_gamma_2
_peak.dexp_rise_alpha_1
_peak.dexp_rise_alpha_2
_peak.dexp_decay_beta_00
_peak.dexp_decay_beta_01
_peak.dexp_decay_beta_10

Total-scattering profiles

Total-scattering peak parameters describe Q-space cutoff, broadening, sharpening, and damping:

_peak.cutoff_q
_peak.broad_q
_peak.sharp_delta_1
_peak.sharp_delta_2
_peak.damp_q
_peak.damp_particle_diameter