Volume 15, Issue 2, February 1944
Index of content:
15(1944); http://dx.doi.org/10.1063/1.1770225View Description Hide Description
The performance of a lithium fluoride prism in an infra‐red spectrograph is described. Coverage of the spectral range from 2 to 5.9μ with considerably higher resolving power than that obtainable with rocksalt is demonstrated. Reproductions of the spectra of several hydrocarbon compounds are included which show the high degree of resolution obtained. The methyl group band at 3.37μ is used as an illustration of the value of the apparatus in the study of molecular structure. As a specific example this group is shown to be absent in polystyrene. It is pointed out that lithium fluoride is inferior to fluorite only because it limits observations to wave‐lengths shorter than 5.9μ.
15(1944); http://dx.doi.org/10.1063/1.1770226View Description Hide Description
A 21‐foot grazing incidence spectrograph, with wave‐length ranges 0–470A and 0–2100A, is described. The use of a single photographic plate 154 cm long, coated on commercial polished plate glass, and a cylindrically ground cast plate holder, makes the dispersion curve smooth and close to the calculated one. Descriptions are given of the mechanical structure; the optical system and the method of focusing; and the electrical system, including a 3‐μf, 70‐kv condenser.
15(1944); http://dx.doi.org/10.1063/1.1770227View Description Hide Description
It is the purpose of this paper to describe a relatively simple x‐ray diffraction apparatus which automatically records, in the form of an inked graph on a moving strip of coordinate paper, diffraction patterns made by substantially pure MoK‐alpha x‐rays. A Mo‐target x‐ray tube is operated in the usual way on a half‐wave rectified 60‐cycle 42‐kvmax circuit. Balanced filters of Zr and Sr are automatically inserted in the path of the incident beam during alternate ``useful'' half‐cycles of the power circuit. The intensities of the two sets of diffracted beams are measured by a Geiger‐Mueller quantum counter, one set of data is electrically subtracted from the other, and the difference (representing the pattern which would have been obtained from a pure MoK‐alpha beam), is automatically recorded in the form of an intensity vs. angle graph.