scholarly journals Stark effect in iron and the contrast with pole effect

1937 ◽  
Vol 162 (910) ◽  
pp. 336-348 ◽  
Author(s):  
S. F. Panter ◽  
John Stuart Foster
Keyword(s):  
Electric Fields ◽  
Stark Effect ◽  
Wave Length ◽  
Operating Conditions ◽  
Large Drop ◽  
Pressure Shift ◽  
Relative Change

In the operating conditions of the iron arc there are a number of influences which may measurably affect the universally accepted standards of wave-lengths. Since this phenomenon appears to have some complexity, it is important to learn what part may be played by pure Stark effect. Already it is known that an increase of pressure within the source causes small shifts in the wave-lengths of most iron lines (pressure shift), which according to Babcock (1928) is always toward the red. This effect appears to be different from the so-called pole effect which consists of a relative change of wave-length at the pole as compared with that at the centre of the arc. For it is found that in the latter effect the shift is toward the red for some lines and toward the violet for others. In recent years the pole effect has been rather generally accepted as a pure Stark effect due to electric fields developed by the relatively large drop of potential near the pole. This view has indeed been taken as a result of earlier examinations of the Stark effect for iron in which the displacements of a few lines were reported to have the same sign as their pole effects.

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 357-362
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

Identification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1998 ◽  
Vol 537 ◽  
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

AbstractIdentification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

scholarly journals Supramolecular Stark Effect in Host-Guest Complexes via Charge Density Analysis

2014 ◽  
Vol 70 (a1) ◽  
pp. C674-C674
Author(s):  
Sajesh Thomas ◽  
Rebecca Fuller ◽  
Alexandre Sobolev ◽  
Philip Schauer ◽  
Simon Grabowsky ◽  
...  
Keyword(s):  
Electric Field ◽  
Charge Density ◽  
Electric Fields ◽  
Active Sites ◽  
Stark Effect ◽  
Dipole Moments ◽  
Covalent Bonds ◽  
Guest Molecules ◽  
Density Mapping ◽  
Density Analysis

The effect of an electric field on the vibrational spectra, the Vibrational Stark Effect (VSE), has been utilized extensively to probe the local electric field in the active sites of enzymes [1, 2]. For this reason, the electric field and consequent polarization effects induced by a supramolecular host system upon its guest molecules attain special interest due to the implications for various biological processes. Although the host-guest chemistry of crown ether complexes and clathrates is of fundamental importance in supramolecular chemistry, many of these multicomponent systems have yet to be explored in detail using modern techniques [3]. In this direction, the electrostatic features associated with the host-guest interactions in the inclusion complexes of halogenated acetonitriles and formamide with 18-crown-6 host molecules have been analyzed in terms of their experimental charge density distribution. The charge density models provide estimates of the molecular dipole moment enhancements which correlate with the simulated values of dipole moments under electric field. The accurate electron density mapping using the multipole formalism also enable the estimation of the electric field experienced by the guest molecules. The electric field vectors thus obtained were utilized to estimate the vibrational stark effect in the nitrile (-C≡N) and carbonyl (C=O) stretching frequencies of the guest molecules via quantum chemical calculations in gas phase. The results of these calculations indicate remarkable elongation of C≡N and C=O bonds due to the electric fields. The electronic polarization in these covalent bonds induced by the field manifests as notable red shifts in their characteristic vibrational frequencies. These results derived from the charge densities are further supported by FT-IR experiments and thus establish the significance of a phenomenon that could be termed as the "supramolecular Stark effect" in crystal environment.

Experimental and Numerical Investigation of Streamwise Surface Waviness on Axial Compressor Blades

2013 ◽  
Author(s):  
Katharina Winter ◽  
Joerg Hartmann ◽  
Peter Jeschke ◽  
Manfred Lahmer
Keyword(s):  
Wave Length ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Surface Waviness ◽  
Compressor Blades ◽  
Industrial Manufacturing ◽  
Numerical Assessment ◽  
Strong Shear ◽  
Two Parameters ◽  
Main Effects

This paper gives an account of an experimental and numerical assessment of the aerodynamic influence of surface imperfections, in the form of sinusoidal waviness, as typically caused by manufacturing malfunctions, on a highly subsonic compressor blade. This knowledge marks a step forward towards an aerodynamically and commercially adequate zero-scrap-rate industrial manufacturing process of expensive integral parts like integrally bladed rotors. The investigation itself used the following approach. First, five potential setups were identified by intensive numerical pre-examination, differing in respect of the two parameters, wave length and wave height. The setups were investigated in the linear cascade wind tunnel of the IST for three operating conditions, with a peak profile Mach number around one, all at constant Reynolds number. It was possible to confirm three main effects responsible for higher losses due to surface waviness. These were: an acceleration on the raising edge of the wave; small shock systems on the first two wave crests; and a shock-induced separation in the wave hollow which leads to a strong shear layer.

scholarly journals Probing Electric Fields in Protein Cavities by Using the Vibrational Stark Effect of Carbon Monoxide

2005 ◽  
Vol 88 (3) ◽  
pp. 1978-1990 ◽  
Author(s):  
Hartwig Lehle ◽  
Jan M. Kriegl ◽  
Karin Nienhaus ◽  
Pengchi Deng ◽  
Stephanus Fengler ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Electric Fields ◽  
Stark Effect

scholarly journals The stark effect in the molecular spectrum of hydrogen

1935 ◽  
Vol 234 (734) ◽  
pp. 115-144 ◽  
Keyword(s):  
Electric Fields ◽  
Stark Effect ◽  
Experimental Information ◽  
Quantum Numbers ◽  
Extensive Analysis ◽  
New Information ◽  
High Fields ◽  
Band Spectra ◽  
Low Dispersion

In considerations of the effect of electric fields on band spectra one finds attention focussed on the secondary spectrum of hydrogen, which alone shows appreciable Stark effect. Following some rather limited observations by early writers, Kiuti has given a more extensive analysis under low dispersion but high fields. This has remained the standard reference in all but the blue and violet regions where MacDonald has given better resolutions, and has succeeded in correlating some of the observed patterns with theory. The rapid advances made by Richardson and others in the classification of the normal H 2 spectrum together with the recent publication by MacDonald of a complete theory for the Stark effect in H 2 have increased enormously the interest attached to further experimental information. In addition, the Stark patterns have been shown to depend upon the rotational quantum numbers, so that the possibility of obtaining new information which may be of assistance in the analysis of the spectrum must not be overlooked.

Sign in / Sign up

Export Citation Format

Share Document