Names,symbols, definitions and units of quantities in optical spectroscopy (Recommendations 1984)

This document gives definitions and recommended names and symbols for the quantities used in the practice of optical spectroscopy (ultraviolet, visible and infrared). An earlier document prepared by our two Commissions (I.5 and VII.2) was entitled “Quantities and units in clinical chemistry. Optical spectroscopy Part 1. Theoretical outline and general quantities (provisional recommendations)”, IUPAC Information Bulletin 1978, No. 3, pp. 241–259. That document was fully comprehensive, and it was considered that for easy reference a shorter and simplified version would be welcomed.The arrangement follows that of the provisional document. After a general introduction explaining the recommendations, the major part of the document is a series of sections, each devoted to one of 17 widely used quantities in molecular spectroscopy. For each quantity there is a definition, a symbol, dimensions and name and symbol of the coherent unit in the SI system. The commonly used multiples of the coherent SI unit are listed together with the corresponding symbols. Alongside are given the commonly used non-SI units which are intended for use when reading older literature. Each section gives common synonyms and other symbols which have been used for the quantity being described, and the choice recommended is justified. Remarks are also given, where appropriate, on the interrelation of symbols.The recommendations conclude with a summary list of the quantities described with symbols, SI units and dimensions, and a bibliography of documents referred to in the text.     

Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008)

IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem. 73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the (1)H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium-3-(trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a part per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic-angle spinning (MAS). This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high-resolution MAS studies. Procedures are given for relating (13)C NMR chemical shifts in solids to the scales used for high-resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids are reviewed in some detail, and recommendations are given for best practice.     

IUPAC Recommendations for Reference Standard Samples in pH Measurements

Consultations

IUPAC Recommendations for Reference Standard Samples in pH Measurements