PERFORMANCE CAPABILITIES OF SMALL GRATING SPECTROMETERS.
Abstract
Some of the performance capabilities of grating infrared spectrometers, such as spectral resolving power, wave-number accuracy, analytical sensitivity and accuracy, and qualitative specificity, are demonstrated. Primary emphasis is given to resolving power and wave-number accuracy. The nu sub 3 fundamental of CH3C1 was studied in the gas phase, and the rotational fine structure was analyzed. A spectral resolution of better than 0.25/cm and a line position accuracy of about plus or minus 0.04/cm were attained. Several rotational constants were determined for CH3C1(35) and CH3C1(37), and these agree well with those previously determined from microwave data. The nu sub 3 and nu sub 4 fundamentals of CH4 were examined in the gas phase with various degrees of resolution, using both prism and grating instruments. With the increased resolution of the grating instruments, striking increases in the peak absorptivities of the rotational lines occur, and many previously unresolved lines appear. This increased resolution gives more specific spectra, leading to greater certainty in the identification of unknowns. Substantial improvements in limits of detectability for simple molecules result, and these molecules can be more certainly identified in mixtures because their rotational spectra can be resolved. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 27, 1966
- Accession Number
- AD0636499
Entities
People
- R. E. Kagarise
Organizations
- United States Naval Research Laboratory