A variation of the classical canal ray source has been developed for the study of the Stark Effect in positive ion lines. Stress was placed on the measurement of small line shifts rather than the attainment of large electric fields. To this end a sensitive shift measuring apparatus employing a linear neutral density filter to translate the line shift into a change in intensity was built. Shifts were measured to an accuracy of about .02 A° in the following lines: He I 5016 A°, 7281 A°, 6678 A°, 3889 A° and Ar I 4272 A°, 4266 A°. No shifts were detected in Ar II 4727 A° and 4806 A°. A discussion of prospective improvements to be made in the apparatus is also included. With these improvements, the apparatus should be capable of measuring shifts to an accuracy of .001 A°. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The electronic emission spectra of the OH and CH molecules in applied electric fields up to 68,000 v/cm have been observed. These spectra show Stark splittings, broadenings and field-induced, parity-forbidden lines. The electric dipole moment of the molecules has been determined for OH in the ²π electronic state and CH in both the ²π and ²∆ electronic states from Stark effects on transitions to the following levels: [formula omitted] Electric fields were determined from Stark splittings in hydrogen Balmer lines. The Stark spectra were produced in the high field region of a low pressure glow discharge. This technique is well suited for the study of short lived and chemically reactive molecules in both their ground and excited, electronic states. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

No description available.

Proefschrift--Universiteit van Amsterdam. / In English. Thesis statement and summary in Dutch. Includes bibliographical references (p. [52]).

Proefschrift Universiteit van Amsterdam. / Met lit.opg.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Population transfer from the valence to conduction band in the presence of an intense laser field is explored theoretically in semiconductors and dielectrics. Experiments on intense laser driven dielectrics have revealed population transfer to the conduction band that differs from that seen in semiconductors. Our research explores two aspects of ionization in solids. (i) Current ionization theories neglect coupling between valence and conduction band and therewith the dynamic Stark shift. Our single-particle analysis identifies this as a potential reason for the different ionization behaviour. The dynamic Stark shift increases the bandgap with increasing laser intensities thus suppressing ionization to an extent where virtual population oscillation become dominant. The dynamic Stark shift plays a role dominantly in dielectrics which due to the large bandgap can be exposed to significantly higher laser intensities. (ii) In the presence of laser dressed virtual population of the conduction band, elastic collisions potentially transmute virtual into real population resulting in ionization. This process is explored in context of relaxation time approximation.

The electronic emission spectra of the CO molecule in an applied electric field of 53.8 kilovolts/cm has been observed. The electric field was determined from the Stark Effect on the H line at 4340Å. The spectra were produced in the high field region of a low pressure glow discharge using carbon monoxide gas and water vapour. The electric dipole moment of the CO molecule has been determined for the BlΣ+ state using the P(l) transition of the Ångstrom ( 0 , 0 ) band. The effect observed is a second order effect in the B1Σ+ state and it has been deduced that the dipole moment of the A1π state is very small or zero. The dipole moment of the B1Σ+ state is 1.61 debye ± 14%. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.