Abstract
A laser spectroscopic method for sensitive electric field measurements using krypton has been developed. The Stark effect of high Rydberg states of the krypton autoionizing series can be measured by a technique called fluorescence dip spectroscopy (FDS) with high spatial and temporal resolution. Calibration measurements have been performed in a reference cell with known electric field and they agree very well with numerical solutions of Schrödinger's equation for jl-coupled states. The application of this method has been demonstrated in the sheath region of a capacitively coupled radiofrequency (RF) discharge. The laser spectroscopic method allows us to add krypton as a small admixture to various low temperature plasmas.
Highlights
Fluorescence dip spectroscopy (FDS) fulfils these requirements when a pulsed laser system is used and the fluorescence is imaged onto a CCD camera
Due to the complex atomic structure, the basic data of the Stark effect have to be obtained at known electric field strengths before it can be applied as a technique for electric field measurement
The first one is a calibration cell for the investigation of the Stark effect at known electric fields and the second one is for space and time resolved electric field measurements in a modified Gaseous Electronics Conference (GEC) reference cell [26]
Summary
The theoretical calculation of the Stark effect in krypton, that is described is based on the calculation for argon atoms developed by Gavrilenko et al [11]. When an electron from the closed outer shell is excited, the spin of the remaining, unpaired electron can have two possible orientations relative to its orbital angular momentum: jc = l0 + s This strongest interaction leads to two separated ionization limits (In krypton, the difference is: ν = 5370 cm−1). The matrix element has to have a nonzero value From this condition, one can obtain the following selection rules for the Stark effect (electric field in z-direction) and for excitation with parallel to the z-axis linearly polarized light, respectively l = ±1,. Rydberg states with large principal quantum numbers n can be approximated very well by a quantum defect formula: From the viewpoint of the excited electron that is predominantly far away from the core, the nucleus with charge Ze is screened by (Z − 1) electrons, resulting in an effective charge q ≈ e ‘felt’ by the electron.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
