Difference between revisions of "Momentum transfer"
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In [[scattering]], the '''momentum transfer''' is a vector in the 3D [[reciprocal-space]] that denotes the change in momentum between the incoming and scattered rays. It thus describes the interaction between the radiation and the sample. This quantity is also frequently called the '''scattering vector''', and is normally denoted by <math>\mathbf{q}</math> or <math>\vec q </math>, in vectorial form, or simply by ''q'' when only the magnitude of the vector is relevant (for 1D scattering; e.g. [[TSAXS]]). | In [[scattering]], the '''momentum transfer''' is a vector in the 3D [[reciprocal-space]] that denotes the change in momentum between the incoming and scattered rays. It thus describes the interaction between the radiation and the sample. This quantity is also frequently called the '''scattering vector''', and is normally denoted by <math>\mathbf{q}</math> or <math>\vec q </math>, in vectorial form, or simply by ''q'' when only the magnitude of the vector is relevant (for 1D scattering; e.g. [[TSAXS]]). | ||
| − | In the majority of scattering experiments ([[SAXS]], [[WAXS]], [[GISAXS]], [[GIWAXS]], etc.), the interaction is elastic, meaning that the [[X-ray energy|energy]] (wavelength) of the incident and scattered photons are equal. In this case, the scattering vector is confined to the surface of the [[Ewald sphere]]. | + | In the majority of scattering experiments ([[SAXS]], [[WAXS]], [[GISAXS]], [[GIWAXS]], etc.), the interaction is elastic, meaning that the [[X-ray energy|energy]] (wavelength) of the incident and scattered photons are equal. In this case, the scattering vector is confined to the surface of the [[Ewald sphere]]. For [[inelastic scattering]], the ''q''-vector is off this surface. |
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| + | ==Definitions== | ||
| + | Some sources use <math>\scriptstyle s</math> instead of <math>\scriptstyle q</math> to denote momentum transfer. | ||
| + | :<math> q = 2 \pi s </math> | ||
| + | |||
| + | ==See Also== | ||
| + | * [[Q value]] (conversion from ''q'' to ''d'') | ||
Latest revision as of 09:49, 25 July 2015
In scattering, the momentum transfer is a vector in the 3D reciprocal-space that denotes the change in momentum between the incoming and scattered rays. It thus describes the interaction between the radiation and the sample. This quantity is also frequently called the scattering vector, and is normally denoted by or , in vectorial form, or simply by q when only the magnitude of the vector is relevant (for 1D scattering; e.g. TSAXS).
In the majority of scattering experiments (SAXS, WAXS, GISAXS, GIWAXS, etc.), the interaction is elastic, meaning that the energy (wavelength) of the incident and scattered photons are equal. In this case, the scattering vector is confined to the surface of the Ewald sphere. For inelastic scattering, the q-vector is off this surface.
Definitions
Some sources use instead of to denote momentum transfer.
See Also
- Q value (conversion from q to d)
