rutherford scattering experiment is related to the size of the nucleus.
rutherford scattering experiment is related to the size of the nucleus.
rutherford scattering experiment is related to the size of?
the nucleus
rutherford scattering is the elastic scattering of charged particles by the coulomb interaction. it is a physical phenomenon explained by ernest rutherford in 1911 that led to the development of the planetary rutherford model of the atom and eventually the bohr model. rutherford scattering was first referred to as coulomb scattering because it relies only upon the static electric (coulomb) potential, and the minimum distance between particles is set entirely by this potential. the classical rutherford scattering process of alpha particles against gold nuclei is an example of "elastic scattering" because neither the alpha particles nor the gold nuclei are internally excited. the rutherford formula (see below) further neglects the recoil kinetic energy of the massive target nucleus.
rutherford scattering
delbrück scattering is the coherent elastic scattering of photons in the coulomb field of heavy nuclei. it is one of the two nonlinear effects of quantum electrodynamics (qed) in the coulomb field investigated experimentally. the other is the splitting of a photon into two photons. delbrück scattering was introduced by max delbrück in order to explain discrepancies between experimental and predicted data in a compton scattering experiment on heavy atoms carried out by meitner and kösters. delbrück’s arguments were based on the relativistic quantum mechanics of dirac according to which the qed vacuum is filled with electrons of negative energy or - in modern terms – with electron-positron pairs. these electrons of negative energy should be capable of producing coherent-elastic photon scattering because the recoil momentum during absorption and emission of the photon is transferred to the total atom while the electrons remain in their state of negative energy. this process is the analog of atomic rayleigh scattering with the only difference that in the latter case the electrons are bound in the electron cloud of the atom. the experiment of meitner and kösters was the first in a series of experiments where the discrepancy between experimental and predicted differential cross sections for elastic scattering by heavy atoms were interpreted in terms of delbrück scattering. from the present point of view these early results are not trustworthy. reliable investigations were possible only after modern qed techniques based on feynman diagrams were available for quantitative predictions, and on the experimental side photon detectors with high energy resolution and high detection efficiency had been developed. this was the case at the beginning of the 1970s when also computers with high computing capacity were in operation which delivered numerical results for delbrück scattering amplitudes with sufficient precision. a first observation of delbrück scattering was achieved in a high-energy, small-angle photon scattering experiment carried out at desy (germany) in 1973, where only the imaginary part of the scattering amplitude is of importance.
delbrück scattering