Fr.: combinaison affine
A linear combination of vectors in which all the vector coefficients add up to one.
1) General: The act of combining or the state of being combined.
Noun from → combine
Fr.: recombinaison dissociative
A process where a positive molecular ion recombines with an electron, and as a result it dissociates into two neutral products. For example, AB+ + e-→ A + B, where e- is an electron, AB+ is a diatomic or polyatomic molecular ion, and A and B are the neutral fragmentation products. Dissociative recombination is the dominant recombination process in planetary ionospheres and interstellar clouds.
Fr.: recombinaison radiative
The process by which an ionized atom binds a free electron in a → plasma to produce a new atomic state with the subsequent radiation of photons.
radio recombination line
xatt-e bâzmiyâzeš-e râdioyi
Fr.: raie de recombinaison radio
A → recombination line whose wavelength lies in the radio range of the electromagnetic spectrum. Radio recombination lines are the result of electronic transitions between high energy levels (n > 50) in an atom or ion.
1) The process or result of combining again.
Verbal noun of → recombine.
Fr.: coefficient de recombinaison
A measure of the specific rate at which oppositely charged ions join to form neutral particles. It is given by the rate at which those ions recombine, divided by the product of the densities of the two species involved.
Fr.: continuum de recombinaison
A recombination radiation that is continuous over a range of frequencies. Same as → continuum emission.
Fr.: époque de recombinaison
Same as → recombination era.
Fr.: ère de recombinaison
The era some 380,000 years after the → Big Bang (at a → redshift of about 1,100), when the Universe had cooled sufficiently so that protons and electrons combined to form → neutral hydrogen in a process called → recombination. The temperature was about 3,000 K and the ionization fraction low enough for Universe to become transparent to light. Consequently matter and radiation decouple from one another because no further → scattering of the radiation occurs. The observation of the → cosmic microwave background radiation provides a means of studying the Universe at the recombination era. Also called recombination epoch and → decoupling era.
Fr.: raie de recombinaison
An → emission line in a spectrum produced in an → H II region when a free electron combines with an ionized atom to form a neutral atom or an ion of lower → ionization stage. Same as → free-bound emission.
Fr.: rayonnement de recombinaison
Radiation produced when a free electron in a plasma is captured by an ionized atom.
Fr.: taux de recombinaison
Fr.: temps de recombinaison
Ritz combination principle
parvaz-e miyâzeš-e Ritz
Fr.: principe de combinaison de Ritz
An empirical rule discovered before the advent of quantum mechanics which states that it is possible to find pairs of spectral lines, which have the property that the sum of their wavenumbers is also an observed spectral line.