Ramsauern.
/ˈramzaʊə/, U.S. /ˈræmˌzaʊər/ Physics.
1.
a. Ramsauer effect n. the sharp decrease, almost to zero, of the scattering cross-section of atoms of inert gases for electrons with energies below a certain critical value. Also called Ramsauer–Townsend effect.
ΘΚΠ
the world > matter > physics > atomic physics > particle physics > action of dispersing particles > [noun] > scattering or energy relationship
Compton effect1924
Ramsauer effect1926
Ramsauer–Townsend effect1952
1926 Proc. National Acad. Sci. U.S.A. 12 465 The Ramsauer effect of great transparency of some atoms for slow electrons.
1963 P. E. Hodgson Optical Model Elastic Scattering v. 90 The physical explanation of the maxima and the minima in the total cross-section..could be ascribed to a nuclear type of Ramsauer effect in which the part of the wave going directly through the nucleus interferes with that going round it.
1996 Physical Rev. C. 54 2014 The small coherent elastic cross section of 48Ca + n is explained through the nuclear Ramsauer effect.
b. Ramsauer minimum n. the minimum in the scattering cross-section for electrons exhibiting the Ramsauer effect. Also called Ramsauer–Townsend minimum.
ΘΚΠ
the world > matter > physics > atomic physics > particle physics > action of dispersing particles > [noun] > scattering or energy relationship > minimum
Ramsauer–Townsend minimum1952
Ramsauer minimum1960
1960 Physical Rev. 117 1416/2 For argon, krypton, and xenon σt(ε) is approximately proportional to ε except below the Ramsauer minimum.
1972 A. Gilardini Low Energy Electron Collisions in Gases iv. 338 Argon has a large Ramsauer minimum at ∼0·3 eV, so that electrons experience far fewer collisions with molecules at these energies.
1998 Chem. Physics Lett. 284 128 Evidence for a Ramsauer minimum is found at about 1 eV collision energy.
2. In general attributive use with reference to the Ramsauer effect.
ΚΠ
1938 L. B. Loeb Atomic Struct. xix. 338 The Ramsauer cross sections..vary in some cases over wide ranges with electron energy.
1943 Philos. Trans. (Royal Soc.) A. 239 287 The mean attachment probability is 2·8 ×10−4 per Ramsauer collision for electrons of mean energy 0·2eV.
1963 Physical Rev. 130 1021/1 His remarkable analysis of the Ramsauer cross sections for argon and krypton.
2005 Jrnl. Physics A 38 8682 The ionization dynamics might be affected by the Ramsauer resonance, a phenomenon well known in atomic collisions of electrons.
This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022).
<
n.1926