Efekt Zeemana – zjawisko fizyczne, które polega na rozszczepieniu obserwowanych linii spektralnych na składowe,
gdy próbka emitująca promieniowanie zostaje umieszczona w polu magnetycznym. Ponieważ odległość między
pod-poziomami Zeemana jest funkcją pola magnetycznego, efekt ten można wykorzystać do pomiaru pola magnetycznego. Efekt Zeemana jest bardzo ważny w zastosowaniach takich jak NMR, EPR, MRI i spektroskopii Mössbauera.
At the root of the Zeemen effect is the subdivision
of the energy levels of atoms and molecules plunged into a magnetic field. According to conditions,
the spectral lines are divided into an odd number
(the effect is said to be “normal”) or an even number (the effect is said to be “abnormal”) of components. This phenomenon is visible to the naked eye or from a computer screen via the didactic webcam provided in this pack.
To observe the Normal effect, we use the mercury lamp with a green filter to select the spectrum and observe only the 546 nm line of mercury leaving the Zeeman box containing the coils and the spectral source. We thus observe our source outside the magnetic field axis, perpendicular to it. We place first a diaphragm, then a condenser. We then place, behind them, the Fabry-Pérot etalon, previously adjusted, and finally our green filter just before placing our CCD sensor. For this exercise, we will not use the sensor lens but a camera lens, to ensure better image quality. We then plug in the power supply and increase slowly the current until we observe the rings that are divided into three. To observe the abnormal effect, we position ourselves in the magnetic field axis without using the diaphragm.
FABRY-PEROT STUDY - FINENESS
To be able to separate the different rings more efficiently, we need to have them as thin as possible. This is equivalent to
refining the peaks in the previous curve, i.e. reduce Δλ with respect to δλ. Thus, a good quality interferometer will exhibit a far lower Δλ than δλ.
The greater the fineness, the finer the rings. To increase fineness, the surfaces making up the cavity can be made highly reflective. Indeed, we can show that fineness increases at the same time as the surface reflection coefficient.
Consequently, Fabry-Perot interferometers can have finenesses of a few dozens or a few hundreds. In research, this can even attain a few hundred thousands. This high degree of fineness is a major asset of this type of interferometers with respect to Michelson’s interferometer, which has a fineness of 2.
Bohr atomic model
Normal and Abnormal effect
POD013550 Zeeman effect pack (Coils set + power supply) x1
POF010112 Optical bench, 1m x1
POF010124 Standard optical rider x6
POD061250 Dual condenser x1
POD060410 iris diaphragm x1
POF020250 Fabry Pérot etalon x1
POM052025 Green filter, plastic x1
POD060230 Slide holder x1
POF010810 Pedagogical webcam with adjustable lens x1
computer is required for the webcam
Stanowisko dostarczamy wraz z propozycjami ćwiczeń.