legay_1955 ========== F\. Legay, "Anomalies de dispersion dans les bandes de vibration\-rotation", Nuovo Cimento 2 \(Suppl\. 3\), 781 \(1955\) `Source record `__ · :doc:`Catalogue ` · :doc:`Review register ` DOI: `10\.1007/bf02822823 `__ **Source kind:** measurement **Recorded technique:** Interferometry inside an infrared absorption band resolved into its lines\: a Twyman interferometer usable to 6 um, LiF plates with a thin selenium film as the beam splitter, a 25 cm gas cell closed by the fixed mirror, a thermometer in the cell and a mercury manometer, lit by a Nernst filament \(p\. 781\); the fringes projected on the slit of a Pfund\-mounted grating spectrograph \(3000 lines per cm, resolving 'environ 3/10 de cm\-1'\) with a PbTe cell cooled by liquid air \(p\. 782\)\. Of the two methods described \(p\. 782\), fringe counting at a fixed wavelength while the cell fills, and the channelled spectrum of a filled, closed cell recorded 'à partir d'une longueur d'onde pour laquelle l'indice est connu', the measurements use the second, 'à différentes pressions' \(p\. 783\)\. The theory curve is Manneback's vibrational term \(Kramers\-Heisenberg with harmonic\-oscillator, rigid\-rotor transition moments; pp\. 782\-783\)\. **Materials in structured entries:** None recorded. **Dataset quantities:** None recorded. **Contents:** 0 datasets; 0 formulas. Curation notes -------------- French\. Page numbers are journal pages \(pdf page \+ 780\)\. The scan \(a page image per page\) prints no DOI; the library found it by a bibliographic search, and the first page's header \(Supplemento al Volume II del Nuovo Cimento, N\. 3, 1955, 2nd semester\), the title, the author and the page headers 782\-784 agree with the record\. ONE GAS, HCl\: the first measurements are of 'la bande de vibration\-rotation fondamentale de l'acide chlorhydrique à 3,4 μ' \(p\. 781\), between the P\(1\) and R\(0\) lines that bound the band's central gap \(p\. 783; in Fig\. 2 the points span about 2866\-2903 cm^\-1, by eye\)\. No other gas is measured\. The introduction names the earlier, prism measurements, 'relativement loin du centre des bandes' and by 'la méthode du prisme, peu précise' \(p\. 781\)\: Statescu \(Phil\. Mag\. 30, 737, 1915\) on CO2, R\. and A\. H\. Rollefson \(Phys\. Rev\. 48, 779, 1935\) on HCl and Rollefson and Havens \(Phys\. Rev\. 57, 710, 1940\) on CH4\. WHAT IS SHOWN\: the values exist only in Fig\. 2 \(p\. 783\), a figure in a scanned page \(raster\)\: ordinate '\(n\_σ \- 1\) 10^6' from \-50 to \+50, abscissa the wavenumber σ, 2860\-2910 cm^\-1, with the theory curve and some 35\-40 measured points\. The curve is the vibrational fundamental's term alone, computed 'à 76 cm de mercure et à 15° C' with the line positions and rotational constants of Mills, Thompson and Williams \(Proc\. R\. Soc\. A 218, 29, 1953\) and Rollefson's effective charge\: 'nous avons complètement négligé les termes contenant les fréquences de rotation et de transition électronique', which hardly vary over so small an interval \(p\. 783\)\. So the ordinate is not the refractivity of HCl\: it changes sign near 2877 cm^\-1\. The points are index variations from a channelled spectrum \(Fig\. 1, p\. 783, at 582 mm Hg and 27\.8 degrees C, p\. 784\)\: 'Les valeurs des variations d'indice ont toutes été rapportées à la pression de 76 cm de mercure et à la température de 15°' \(p\. 784\)\. How their zero was set against the curve, and which reference wavelength and index the channelled spectrum started from, is not stated; nor is how the variations were scaled to 76 cm Hg and 15 degrees C \(ideal or real gas\)\. ACCURACY\: no uncertainty is stated\. 'Les points expérimentaux se placent assez bien sur la courbe théorique \(fig\. 2\)', and the author means later to increase the precision and to come closer to the line centres \(p\. 784\)\. The wavelength medium is not stated \(the abscissa is in cm^\-1\)\. NOT CURATED\: HCl is not a registered material, and the values are relative variations inside an absorption band, with an unstated zero, read only from a raster figure \(the figure rule, TC\-699\)\. There are no data for CO, CO2, CH4 or N2O, the gases of TC\-756\: no datasets\. **Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents. Datasets -------- No datasets are recorded. Formulas -------- No formulas are recorded. Corrections ----------- No dataset errata are recorded in this source record. Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register ` for the checks and decisions.