The xraylib API list of all functions - tschoonj/xraylib GitHub Wiki

Important: release 4.0.0 introduces a new error handling mechanism, that will affect all xraylib users, especially those writing code in C and C++. Please ensure you have read and understood the section on error handling if using either of these two languages.

This page lists the xraylib API as it is used from C, C++ and Objective-C. If using a different language, ignore the last argument xrl_error **error.

Unless explicitly stated otherwise, all energies are assumed to be expressed in keV, whether used as input argument or return value. Similarly, all angles are assumed to be expressed in radians.

Atomic weights

double AtomicWeight(int Z, xrl_error **error);

Given an element Z, returns its atomic weight in g/mol.

Element densities

double ElementDensity(int Z, xrl_error **error);

Given an element Z, returns its density at room temperature in g/cm3.

Cross sections

double CS_Total(int Z, double E, xrl_error **error);
double CS_Photo(int Z, double E, xrl_error **error);
double CS_Rayl(int Z, double E, xrl_error **error);
double CS_Compt(int Z, double E, xrl_error **error);

Given an element Z and an energy E , these functions will return respectively the total attenuation cross section, the photoionization cross section, the Rayleigh scattering cross section and the Compton scattering cross section, expressed in cm2/g.

double CSb_Total(int Z, double E, xrl_error **error);
double CSb_Photo(int Z, double E, xrl_error **error);
double CSb_Rayl(int Z, double E, xrl_error **error);
double CSb_Compt(int Z, double E, xrl_error **error);

Identical to the last four functions, but the cross section is returned expressed in barn/atom.

double CS_KN(double E, xrl_error **error);

Given an energy E , returns the total Klein-Nishina cross section expressed in barn.

double CS_Photo_Partial(int Z, int shell, double E, xrl_error **error);

Given an element Z, shell-type macro shell and energy E, returns the partial photoionization cross section expressed in cm2/g.

double CSb_Photo_Partial(int Z, int shell, double E, xrl_error **error);

Identical to the last function, but the cross section is returned in barn/electron.

double CS_Total_Kissel(int Z, double E, xrl_error **error);
double CSb_Total_Kissel(int Z, double E, xrl_error **error);

Identical to CS_Total and CSb_Total, but the photoionization contribution is calculated using the Kissel cross sections.

double CS_Energy(int Z, double E, xrl_error **error);

Given an element Z and an energy E, returns the mass-energy absorption cross section in cm2g

double CS_Total_CP(const char compound[], double E, xrl_error **error);
double CS_Photo_CP(const char compound[], double E, xrl_error **error);
double CS_Rayl_CP(const char compound[], double E, xrl_error **error);
double CS_Compt_CP(const char compound[], double E, xrl_error **error);
double CSb_Total_CP(const char compound[], double E, xrl_error **error);
double CSb_Photo_CP(const char compound[], double E, xrl_error **error);
double CSb_Rayl_CP(const char compound[], double E, xrl_error **error);
double CSb_Compt_CP(const char compound[], double E, xrl_error **error);
double CS_Total_Kissel_CP(const char compound[], double E, xrl_error **error);
double CSb_Total_Kissel_CP(const char compound[], double E, xrl_error **error);
double CS_Energy(const char compound[], double E, xrl_error **error);

Identical to the earlier mentioned functions, but require a chemical formula or a NIST compound name compound as first argument.

Unpolarized differential scattering cross sections

double DCS_Thoms(double theta, xrl_error **error);

Given a scattering polar angle theta, returns the Thomson differential cross section expressed in barn.

double DCS_KN(double E, double theta, xrl_error **error);

Given an energy E and a scattering polar angle theta, returns the Klein-Nishina differential scattering cross section expressed in barn.

double DCS_Rayl(int Z, double E, double theta, xrl_error **error);
double DCS_Compt(int Z, double E, double theta, xrl_error **error);

Given an element Z, energy E and a scattering polar angle theta , returns respectively the differential Rayleigh and the differential Compton scattering cross section expressed in cm2/g/sterad.

double DCSb_Rayl(int Z, double E, double theta, xrl_error **error);
double DCSb_Compt(int Z, double E, double theta, xrl_error **error);

Identical to the last two functions, but the cross section is returned expressed in barn/atom/sterad.

double DCS_Rayl_CP(const char compound[], double E, double theta, xrl_error **error);
double DCS_Compt_CP(const char compound[], double E, double theta, xrl_error **error);
double DCSb_Rayl_CP(const char compound[], double E, double theta, xrl_error **error);
double DCSb_Compt_CP(const char compound[], double E, double theta, xrl_error **error);

Identical to the earlier mentioned functions, but require a chemical formula or a NIST compound name compound as first argument.

Polarized differential scattering cross sections

double DCSP_Thoms(double theta, double phi, xrl_error **error);

Given a scattering polar angle theta and scattering azimuthal angle phi, returns the Thomson differential cross section for a polarized beam expressed in barn.

double DCSP_KN(double E, double theta, double phi, xrl_error **error);

Given an energy E, a scattering polar angle theta and scattering azimuthal angle phi, returns the Klein-Nishina differential cross section for a polarized beam expressed in barn.

double DCSP_Rayl(int Z, double E, double theta, double phi, xrl_error **error);
double DCSP_Compt(int Z, double E, double theta, double phi, xrl_error **error);

Given an element Z, an energy E , a scattering polar angle theta and scattering azimuthal angle phi, returns respectively the Rayleigh differential and Compton differential cross sections for a polarized beam expressed in cm2/g/sterad.

double DCSPb_Rayl(int Z, double E, double theta, double phi, xrl_error **error);
double DCSPb_Compt(int Z, double E, double theta, double phi, xrl_error **error);

Identical to the last two functions, but the cross section is returned expressed in barn/atom/sterad.

double DCSP_Rayl_CP(const char compound[], double E, double theta, double phi, xrl_error **error);
double DCSP_Compt_CP(const char compound[], double E, double theta, double phi, xrl_error **error);
double DCSPb_Rayl_CP(const char compound[], double E, double theta, double phi, xrl_error **error);
double DCSPb_Compt_CP(const char compound[], double E, double theta, double phi, xrl_error **error);

Identical to the earlier mentioned functions, but require a chemical formula or a NIST compound name compound as first argument.

Scattering factors

In this section, we introduce the momentum transfer parameter q, which is used in several of the following functions. It should be noted that several definitions can be found of this parameter throughout the scientific literature, which vary mostly depending on the community where it is used. The crystallography and diffraction community for example, use the following definition:

q = 4π × sin(θ)/λ

with θ the angle between the incident X-ray and the crystal scattering planes according to Bragg's law, and λ the wavelength. xraylib uses however, a different definition, in which θ corresponds to the scattering angle, which in case of Bragg scattering is equal to twice the angle from the previous definition. This new definition has the advantage of being useful when working with amorphous materials, as well as with incoherent scattering. Furthermore, our definition drops the 4π scale factor, in line with the definition by Hubbell et al in Atomic form factors, incoherent scattering functions, and photon scattering cross sections, J. Phys. Chem. Ref. Data, Vol.4, No. 3, 1975:

q = E × sin(θ/2) × h × c × 108

with E the energy of the photon, h Planck's constant and c the speed of light. The unit of the returned momentum transfer is then Å-1.

double  FF_Rayl(int Z, double q, xrl_error **error);

Given an element Z and a momentum transfer q (expressed in Å-1), returns the atomic form factor for Rayleigh scattering.

double  SF_Compt(int Z, double q, xrl_error **error);

Given an element Z and a momentum transfer q (expressed in Å-1), returns the incoherent scattering function for Compton scattering.

double  MomentTransf(double E, double theta, xrl_error **error);

Given an energy E and a scattering polar angle theta, returns the momentum transfer for X-ray photon scattering expressed in Å-1.

double Fi(int Z, double E, xrl_error **error);
double Fii(int Z, double E, xrl_error **error);

Given an element Z and and energy E, returns respectively the anomalous scattering factors Δf′ and Δf″.

X-ray fluorescence line energies

double LineEnergy(int Z, int line, xrl_error **error);

Given an element Z and line-type macro line, returns the energy of the requested XRF line expressed in keV.

X-ray fluorescence yields

double  FluorYield(int Z, int shell, xrl_error **error);

Given an element Z and shell-type macro shell, returns the corresponding fluorescence yield .

Auger yields

double  AugerYield(int Z, int shell, xrl_error **error);

Given an element Z and shell-type macro shell, returns the corresponding Auger yield .

Coster-Kronig transition probabilities

double  CosKronTransProb(int Z, int trans, xrl_error **error);

Given an element Z and transition-type macro trans, returns the corresponding Coster-Kronig transition probability.

Absorption edge energies

double EdgeEnergy(int Z, int shell, xrl_error **error);

Given an element Z and shell-type macro shell, returns the absorption edge energy expressed in keV.

Jump factors

double JumpFactor(int Z, int shell, xrl_error **error);

Given an element Z and shell-type macro shell, returns the jump factor.

X-ray fluorescence cross sections

double CS_FluorLine(int Z, int line, double E, xrl_error **error);

Given an element Z, a line-type macro line and an energy E, returns the XRF cross section expressed in cm2/g

double CSb_FluorLine(int Z, int line, double E, xrl_error **error);

Identical to the previous function, but returns the cross section expressed in barn/atom. These last two functions calculate the XRF cross sections assuming the jump factor approximation. We also offer XRF cross sections calculated using the partial photoelectric effect cross sections calculated by Kissel et al. The corresponding functions are:

double CS_FluorLine_Kissel(int Z, int line, double E, xrl_error **error);
double CSb_FluorLine_Kissel(int Z, int line, double E, xrl_error **error);

Recently we introduced XRF cross sections that take into account cascade effects, both those coming from radiative transitions and those from non-radiative transitions :

double CS_FluorLine_Kissel_Cascade(int Z, int line, double E, xrl_error **error);
double CSb_FluorLine_Kissel_Cascade(int Z, int line, double E, xrl_error **error);
double CS_FluorLine_Kissel_Nonradiative_Cascade(int Z, int line, double E, xrl_error **error);
double CSb_FluorLine_Kissel_Nonradiative_Cascade(int Z, int line, double E, xrl_error **error);
double CS_FluorLine_Kissel_Radiative_Cascade(int Z, int line, double E, xrl_error **error);
double CSb_FluorLine_Kissel_Radiative_Cascade(int Z, int line, double E, xrl_error **error);
double CS_FluorLine_Kissel_no_Cascade(int Z, int line, double E, xrl_error **error);
double CSb_FluorLine_Kissel_no_Cascade(int Z, int line, double E, xrl_error **error);

CS_FluorLine_Kissel and CbS_FluorLine_Kissel are mapped to resp. CS_FluorLine_Kissel_Cascade and CSb_FluorLine_Kissel_Cascade. Using these functions, it is possible to examine the influence of the two different cascade types separately, but keep in mind that in reality they will always be occuring simultaneously.

All CS_FluorLine* functions offer XRF cross sections for both K- and L-lines (provided the corresponding shells can be excited), but only the CS_FluorLine_Kissel* functions offer also the M-line XRF cross sections!

Often one will want to get the XRF production cross sections for multiple lines that result from an excitation of the same shell. If this has to be done many times, it may slow down your code tremendously. To overcome this, we introduced a new family of functions CS_FluorShell that return the XRF production cross section for a whole shell, instead of an individual line.

double CS_FluorShell(int Z, int shell, double E, xrl_error **error);
double CSb_FluorShell(int Z, int shell, double E, xrl_error **error);
double CS_FluorShell_Kissel(int Z, int shell, double E, xrl_error **error);
double CSb_FluorShell_Kissel(int Z, int shell, double E, xrl_error **error);
double CS_FluorShell_Kissel_Cascade(int Z, int shell, double E, xrl_error **error);
double CSb_FluorShell_Kissel_Cascade(int Z, int shell, double E, xrl_error **error);
double CS_FluorShell_Kissel_Nonradiative_Cascade(int Z, int shell, double E, xrl_error **error);
double CSb_FluorShell_Kissel_Nonradiative_Cascade(int Z, int shell, double E, xrl_error **error);
double CS_FluorShell_Kissel_Radiative_Cascade(int Z, int shell, double E, xrl_error **error);
double CSb_FluorShell_Kissel_Radiative_Cascade(int Z, int shell, double E, xrl_error **error);
double CS_FluorShell_Kissel_no_Cascade(int Z, int shell, double E, xrl_error **error);
double CSb_FluorShell_Kissel_no_Cascade(int Z, int shell, double E, xrl_error **error);

The relationship between the CS_FluorLine and CS_FluorShell function can be expressed as:

CS_FluorLine = CS_FluorShell * RadRate

Care needs to be taken to use the correct shell and line macros!

Radiative rates

double RadRate(int Z, int line, xrl_error **error);

Given an element Z and a line-type macro line, returns the radiative rate.

Non-radiative rates

double AugerRate(int Z, int auger, xrl_error **error);

Given an element Z and an Auger-type macro auger corresponding with the electrons involved, returns the non-radiative rate.

Atomic level widths

double AtomicLevelWidth(int Z, int shell, xrl_error **error);

Given an element Z and a shell-type macro shell, returns the atomic level width in keV.

Compton energy

double ComptonEnergy(double E0, double theta, xrl_error **error);

Given an initial photon energy E0 and a scattering polar angle theta, returns the photon energy after Compton scattering.

Refractive indices

double Refractive_Index_Re(const char compound[], double E, double rho, xrl_error **error);
double Refractive_Index_Im(const char compound[], double E, double rho, xrl_error **error);
xrlComplex Refractive_Index(const char compound[], double E, double rho, xrl_error **error);

Given a chemical formula compound, energy E and a density rho (expressed in g/cm3), return respectively the real, the imaginary or both parts of the refractive index. For a definition of xrlComplex, see the crystal diffraction section.

Compton profiles

double ComptonProfile(int Z, double pz, xrl_error **error);

Given an element Z and a momentum pz (expressed in atomic units), returns the Compton scattering profile summed over all shells.

double ComptonProfile_Partial(int Z, int shell, double pz, xrl_error **error);

Given an element Z, a shell-type macro shell and a momentum pz, returns the Compton scattering profile for a particular subshell.

Electronic configurations

double ElectronConfig(int Z, int shell, xrl_error **error);

Given an element Z and a shell-type macro shell , returns the number of electrons the shell possesses.

Crystal diffraction

Crystal_Struct* Crystal_GetCrystal(const char* material, Crystal_Array* c_array, xrl_error **error);

Get a pointer to a Crystal_Struct of a given crystal material from c_array. If c_array is NULL then the internal array of crystals is searched. If not found, NULL is returned. The c_array argument is only used in C, C++ and Fortran. The other bindings support only the internal array.

char **Crystal_GetCrystalsList(Crystal_Array *c_array, int *nCrystals, xrl_error **error);

Get a NULL-terminated array of the names of the crystals in c_array. If c_array is NULL, the internal array of crystals will be used. If nCrystals is not NULL, it shall receive the number of crystalnames in the array. The returned array should be freed firstly by using xrlFree to deallocate all individual strings, and subsequently by using xrlFree to deallocate the array itself. The c_array argument is only used in C, C++ and Fortran. The other bindings support only the internal array. The nCrystals argument is used only in C and C++.

double Bragg_angle (Crystal_Struct* cryst, double E, int i_miller, int j_miller, int k_miller, xrl_error **error);

Computes the Bragg angle in radians for a given crystal cryst, energy E and Miller indices i_miller, j_miller and k_miller.

double Q_scattering_amplitude(Crystal_Struct* cryst, double E, int i_miller, int j_miller, int k_miller, double rel_angle, xrl_error **error);

Computes the Q scattering amplitude for a given crystal cryst, incident energy E, Miller indices (i_miller, j_miller and k_miller) and relative angle rel_angle.

void Atomic_Factors (int Z, double E, double q, double debye_factor, double* f0, double* f_prime, double* f_prime2, xrl_error **error);

Computes the atomic factors f0 f0, Δf′ f_prime and Δf″ f_prime2 for a given element Z, incident energy E, momentum transfer q and Debye factor debye_factor. f0, f_prime and f_prime2 are pointers to doubles in C, C++, Fortran and IDL BUT return values in all other languages!!

xrlComplex Crystal_F_H_StructureFactor (Crystal_Struct* cryst, double E, int i_miller, int j_miller, int k_miller, double debye_factor, double rel_angle, xrl_error **error);

Computes the F_H Structure factor for a given crystal cryst, incident energy E, Miller indices (i_miller, j_miller and k_miller), Debye factor debye_factor and relative angle rel_angle. The return value is a complex number.

xrlComplex Crystal_F_H_StructureFactor_Partial (Crystal_Struct* crystal, double energy, int i_miller, int j_miller, int k_miller, double debye_factor, double rel_angle, int f0_flag, int f_prime_flag, int f_prime2_flag, xrl_error **error);

with:

typedef struct {
	double re;
	double im;
} xrlComplex;

with:

  • re: real part
  • im: imaginary part

Wherever possible for the bindings (Python, IDL, Perl, Ruby, Fortran, C#), we have tried using the native complex number datatype in favor of a direct analogue of the xrlComplex struct.

See also Crystal_F_H_StructureFactor.

The Atomic structure factor has three terms:

FH = f0 + Δf′ + Δf″.

For each of these three terms, there is a corresponding *_flag argument which controls the numerical value used in computing FH:

*_flag = 0 → Set this term to 0.

*_flag = 1 → Set this term to 1. Only used for f0.

*_flag = 2 → Set this term to the value given.

double Crystal_UnitCellVolume (Crystal_Struct* cryst, xrl_error **error);

Computes the unit cell volume for a crystal cryst. Structures obtained from the official array will have their volume in .volume

double Crystal_dSpacing (Crystal_Struct* cryst, int i_miller, int j_miller, int k_miller, xrl_error **error);

Computes the d-spacing for a given crystal cryst and Miller indices (i_miller, j_miller and k_miller). The routine assumes that if cryst->volume is nonzero then it holds a valid value. If (i,j,k) = (0,0,0) then zero is returned.

Compound parser

struct compoundData {
	int nElements;
	double nAtomsAll;
	int *Elements;
	double *massFractions;
	double *nAtoms;
	double molarMass;
};

with:

  • nElements: number of different elements in the compound
  • nAtomsAll: number of atoms in the formula. Since indices may be real numbers, this member variable is of type double
  • Elements: a dynamically allocated array (length = nElements) containing the elements, in ascending order
  • massFractions: a dynamically allocated array (length = nElements) containing the mass fractions of the elements in Elements
  • nAtoms: a dynamically allocated array (length = nElements) containing the number of atoms each element has in the compound.
  • molarMass: the molar mass of the compound, in g/mol
struct compoundData *CompoundParser(const char compoundString[], xrl_error **error)

The CompoundParser function will parse a chemical formula compoundString and will allocate a compoundData structure with the results if successful, otherwise NULL is returned. Chemical formulas may contain (nested) brackets, followed by an integer or real number (with a dot) subscript. Examples of accepted formulas are: H2O, Ca5(PO4)3F, Ca5(PO4)F0.33Cl0.33(OH)0.33.

The allocated memory should be freed with

FreeCompoundData(struct compoundData *cd); (C/C++/Obj-C/Pascal only)
char * AtomicNumberToSymbol(int Z, xrl_error **error);

The AtomicNumberToSymbol function returns a pointer to a string containing the element for atomic number Z. If an error occurred, the NULL string is returned. The string should be freed after usage with the xrlFree function (C/C++/Obj-C and Fortran only).

int SymbolToAtomicNumber(char *symbol, xrl_error **error);

The SymbolToAtomicNumber function returns the atomic number that corresponds with element symbol. If the element does not exist, 0 is returned.

NIST compound catalog

struct compoundDataNIST {
	char *name;
	int nElements;
	int *Elements;
	double *massFractions;
	double density;
};

with:

  • name: a string containing the full name of the compound, as retrieved from the NIST database
  • nElements: number of different elements in the compound
  • Elements: a dynamically allocated array (length = nElements) containing the elements, in ascending order
  • massFractions: a dynamically allocated array (length = nElements) containing the mass fractions of the elements in Elements
  • density: the density of the compound, expressed in g/cm3 
struct compoundDataNIST *GetCompoundDataNISTByName(const char compoundString[], xrl_error **error);

struct compoundDataNIST *GetCompoundDataNISTByIndex(int compoundIndex, xrl_error **error);

Using these two functions it is possible to query the contents of NISTs catalog of compound compositions and densities. The former takes a compound name compoundString and if a match is found, the corresponding newly allocated compoundDataNIST structure is returned, while the latter takes an index compoundIndex in the form of a NIST compound-type macro. The list of compound names can be queried using:

char **GetCompoundDataNISTList(int *nCompounds, xrl_error **error);

which returns a NULL terminated array of strings. Optionally, pass a pointer to an integer nCompounds to obtain the number of strings in the array (pass NULL if value is not required). This option is only present in the C/C++/Obj-C implementation. The list can also be obtained at our online xraylib calculator.

After usage, the returned compoundDataNIST structures should be freed with (C/C++/Obj-C/Pascal only):

void FreeCompoundDataNIST(struct compoundDataNIST *compoundData);

Radionuclides

struct radioNuclideData {
	char *name;
	int Z;
	int A;
	int N;
	int Z_xray;
	int nXrays;
	int *XrayLines;
	double *XrayIntensities;
	int nGammas;
	double *GammaEnergies;
	double *GammaIntensities;
};

with:

  • name: a string containing the mass number (A), followed by the chemical element (e.g. 55Fe)
  • Z: atomic number of the radionuclide
  • A: mass number of the radionuclide
  • N: number of neutrons of the radionuclide
  • Z_xray: atomic number of the nuclide after decay, which should be used in calculating the energy of the emitted X-ray lines using LineEnergy
  • nXrays: number of emitted characteristic X-rays
  • XrayLines: a dynamically allocated array (length = nXrays) of line-type macros, identifying the emitted X-rays
  • XrayIntensities: a dynamically allocated array (length = nXrays) of photons per disintegration, one value per emitted X-ray
  • nGammas: number of emitted gamma-rays
  • GammaEnergies: a dynamically allocated array (length = nGammas) of emitted gamma-ray energies
  • GammaIntensities: a dynamically allocated array (length = nGammas) of emitted gamma-ray photons per disintegration
struct radioNuclideData *GetRadioNuclideDataByName(const char radioNuclideString[], xrl_error **error);

struct radioNuclideData *GetRadioNuclideDataByIndex(int radioNuclideIndex, xrl_error **error);

Use these two functions to query xraylib's database of X-ray emission profiles for several important radionuclides. The former expects the name radioNuclideString of a radionuclide, while the latter takes a radionuclide-type macro radioNuclideIndex. When successful, a freshly allocated radioNuclideData structure is returned. Query the list of names using:

char **GetRadioNuclideDataList(int *nRadioNuclides, xrl_error **error);

which returns a NULL terminated array of strings. Optionally, pass a pointer to an integer nRadioNuclides to obtain the number of strings in the array (pass NULL if value is not required). This option is only present in the C/C++/Obj-C implementation. The list can also be obtained at our online xraylib calculator.

After usage, the returned radioNuclideData structures should be freed with (C/C++/Obj-C/Pascal only):

void FreeRadioNuclideData(struct radioNuclideData *radioNuclideData);
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