The separated-oscillatory-field technique is used to narrow the Lamb-shift resonance below its natural width of 100 MHz. A beam of fast hydrogen atoms is passed through two separated, coherent ...oscillatory fields, and the surviving number of metastable atoms is monitored by observing the Lyman-alpha photons emitted in Stark-induced decay to the ground state. However, the improved measurement of the Lamb shift in hydrogen that is presented is in poor agreement with QED predictions. It is noted that if these discrepancies persist they may serve as important clues to the approximations inherent in our present understanding of electromagnetic interactions.
This paper reports measurements of the lifetimes of fourteen levels in the 3s, 3d complex of para-H2 by a delayed coincidence method. A collimated beam of metastable hydrogen molecules was ...selectively excited by light pulses from a CW dye laser and fluorescent radiation was detected by a vacuum ultraviolet photomultiplier. The observed lifetimes range from 11.1 to 48.8 nsec. Similar methods can be used to determine the structure and lifetimes in other excited states of H2 and in a variety of other systems.
The combination of a fast atom or ion beam derived from a small accelerator with radiofrequency spectroscopy methods provides a powerful method for measuring the fine structure of atomic and ...molecular systems. The fast beam makes possible measurements in which two separated oscillatory fields are used to obtain resonance lines whose widths are less than the natural line width due to the lifetimes of the states. The separated oscillatory field lines have, in addition, a number of features which make possible measurements with greater precision and less sensitivity to systematic errors. The fast beam also makes accessible multiple photon radiofrequency transitions whose line width is intrinsically narrower than that of the single photon transitions and which offer great potential for high precision measurements. This report focuses on the techniques and their promise. Recent measurements of the fine structure of H and He+ are used as illustrations.
