Recommendations are given for metrological terminology in analytical chemistry. Analytical chemistry is defined, and concepts related to laboratory practice are termed and defined. Recommendations are given concerning the terminology of quality assurance in analytical chemistry. Terms draw on the extensive quality literature, particularly from ISO.

Recommendations are given for metrological terminology in analytical chemistry. Analytical chemistry is defined, and concepts related to laboratory practice are termed and defined. Recommendations are given concerning the terminology of quality assurance in analytical chemistry. Terms draw on the extensive quality literature, particularly from ISO.

A strong vibration can cause the refractive index, n, to attain values below unity. On the high-wavenumber side of this interval where n matches unity, unexpected reflection anomalies occur which can result in features pronounced enough to dominate the ellipsometric spectra. Even though being of similar shape, these features do not indicate a vibration but indicate sample properties such as the existence of a surface layer or anisotropy, which have to be taken into account when evaluating the spectra. Examples observed with glass, quartz, and a polymer (PTFE) are presented.

The vibrational characteristics of the nitro group (-NO 2 ) in long-chain organic molecules, deposited as oriented thin films on metallic or semiconductor surfaces, are discussed. The dependence of the ellipsometric spectra on the average orientation of the vibrational transition moments of the -NO 2 group in the aligned organic films is addressed. As illustrative examples, the ellipsometric spectra of a 60 nm thick Langmuir-Blodgett film of 2-[4-(N-dodecanoyl-amino)phenyl]-5-(4-nitrophenyl)-l,3,4-oxadiazole either on gold or on silicon, as well as a 2.5 nm thick self-assembled monolayer (SAM) of 4-nitrobenzyl-16-mercaptohexadecanoate on silver, are presented. The -NO 2 resonance frequencies, oscillator strengths and damping constants determined for the Langmuir-Blodgett film on gold were used to evaluate the change in the tilt angle after the film had been annealed at 130°C. The same values were further employed to reveal the orientation of such a film on silicon and to analyze the self-assembled monolayer on silver.

Spectral ellipsometry has developed into a routine method applicable to the infrared spectral range. It can give both the refractive index (n) and the absorption index (k), which has so far only been determined for a limited number of compounds. It turns out that vibrations that have a dispersion with an interval of n<1 are by no means restricted to crystals, but occur with numerous compounds including polymers and liquids. In conventional infrared spectroscopy, one usually is not aware of such a situation and so the consequences are disregarded. These include the so-called reststrahlen (residual rays) bands and specific phenomena that occur when n matches the absorption index (the Berreman effect) or the refractive index of ambient air (vanishing reflection, the Christiansen effect). These and some typical applications are discussed, including model calculations and experimental data.