Gold Book Terms - A
'A' value A-factor \(A\)ab initio calculations ab initio quantum mechanical methods abatement in atmospheric chemistryabeo- abiological abiotic abiotic transformation absolute activation analysis absolute activity \(\lambda\)absolute configuration absolute counting in radioanalytical chemistryabsolute electrode potential absolute full energy peak efficiency absolute lethal concentration \(\text{LC}_{100}\)absolute lethal dose \(\text{LD}_{100}\)absolute photopeak efficiency absolute preconcentration in trace analysisabsorbance matching in spectrochemical analysisabsorbance \(A\)absorbed (spectral) photon flux density absorbed (spectral) radiant power density absorbed dose of a substanceabsorbed dose \(D\) of radiationabsorbed electron coefficient in in situ microanalysisabsorbed electrons in in situ microanalysisabsorber absorptance \(\alpha\)absorption absorption coefficient absorption coefficient in biologyabsorption cross-section \(\sigma\)absorption factor absorption intensity absorption line absorption pathlength of a sample cellabsorption spectrum absorptivity abstraction abstraction process in catalysisabundance sensitivity in mass spectrometryac accelerating voltage scan \(\text{V}\) in mass spectrometryacceleration energy in in situ microanalysisacceleration of free fall \(g\)acceleration \(a\)accelerator in solvent extractionacceptable daily intake acceptor number \(\text{AN}\)accommodation coefficient accretion in atmospheric chemistryaccuracy of a measuring instrumentaccuracy of measurementacenes acetals acetogenins acetonides acetylene black acetylenes acetylides Acheson graphite achiral achirotopic aci-nitro compounds acid acid anhydrides acid deposition in atmospheric chemistryacid rain in atmospheric chemistryacid thioanhydrides acid-labile sulfur acid–base indicator acid–base titration acidimetric titration acidity of a mediumacidity constant acidity function acidosis actinic actinic flux \(S_{\lambda}\)actinism actinometer action spectrum activated adsorption process activated carbon activated charcoal activated complex activation activation analysis (nuclear) activation cross-section activation energy activation in electrochemical corrosionactivation in radiochemistryactivation reaction activator active centre active medium active metal in electrochemical corrosionactive site in heterogeneous catalysisactive solid active species active state in electrochemical corrosionactive transport in biologyactivity activity \(a\)activity coefficient \(f\),\(\gamma \)activity \(A\) of a radioactive materialacute toxicity acyl anions acyl carbenes acyl cations acyl groups acyl halides acyl radicals acyl shift (1,2-, 1,3-, photochemical) acyl species acylals acylium ions acyloins acyloxyl radicals added hydrogen addend addition addition reaction additive additive name additivity of mass spectraadditivity principle adduct adduct ion in mass spectrometryadhesional wetting adiabatic adiabatic electron transfer adiabatic ionization in mass spectrometryadiabatic lapse rate in atmospheric chemistryadiabatic photoreaction adiabatic transition-state theory adiabatic treatments of reaction rates adjacent re-entry model in polymer crystalsadjusted retention volume adjuvant in immunologyADMR adsorbate adsorbent adsorber adsorption adsorption capacity adsorption chromatography adsorption complex adsorption current adsorption hysteresis adsorption indicator adsorption isobar adsorption isostere adsorption isotherm in chromatographyadsorptive advancement advection in atmospheric chemistryadverse effect aeration in atmospheric chemistryaerobe aerobic aerobic conditions aerogel aerometer in atmospheric chemistryaerometric measurement in atmospheric chemistryaerosol aerosol hydrolysis affine chain behaviour affinity chromatography affinity of reaction \(A\)after mass analysis in mass spectrometryageing of precipitate of precipitateagglomerate in catalysisagglomerate in polymer scienceagglomeration (except in polymer science) agglomeration in polymer scienceagglutination aggregate in catalysisaggregation (except in polymer science) aging of a polymeraglycon agonist agostic agostic interaction agranular carbon air contaminant in atmospheric chemistryair mass in atmospheric chemistryair monitoring station in atmospheric chemistryair pollutant air pollution air pollution index air pollution survey in atmospheric chemistryair quality characteristic in atmospheric chemistryair resource management in atmospheric chemistryair sampling network in atmospheric chemistryair-lift bioreactor Aitken particles albedo albumin alcogel alcoholates alcohols alcoholysis aldaric acids aldazines aldehydes aldimines alditols aldoketoses aldonic acids aldoses aldoximes alert levels in atmospheric chemistryalicyclic compounds aliphatic compounds aliquot in analytical chemistryalkalimetric titration alkaloids alkalosis alkanes alkanium ions alkene photocycloaddition alkene photodimerization alkene photoisomerization alkene photorearrangement alkenes alkoxides alkoxyamines alkyl groups alkyl radicals alkylenes alkylidene groups alkylideneamino carbenes alkylideneaminoxyl radicals alkylideneaminyl radicals alkylidenes alkylidynes alkynes allele allenes allo- in amino-acid nomenclatureallometric allosteric enzymes allostery allotriomorphic transition allotropes allotropic transition allylic groups allylic intermediates allylic substitution reaction alternancy symmetry alternant alternating copolymer alternating copolymerization alternating current alternating voltage altocumulus cloud in atmospheric chemistryaltostratus cloud in atmospheric chemistryAM 0 sunlight AM 1 sunlight amalgam lamp ambident ambient air in atmospheric chemistryambient air quality in atmospheric chemistryambo Ames/salmonella test amic acids amide hydrazones amide oximes amides amidines amidium ions amidrazones aminals amine imides amine imines amine oxides amine ylides amines aminimides aminium ions aminiumyl radical ions amino radicals amino sugars amino-acid residue in a polypeptideaminonitrenes aminooxyl radicals aminoxides aminoxyl radicals aminyl oxides aminyl radicals aminylenes aminylium ions ammonium compounds ammonium imines ammonium ylides ammoniumyl radical ions amorphous carbon amount concentration \(c\)amount fraction x (y for gaseous mixtures) amount of substance \(n\)amount-of-substance concentration amount-of-substance fraction \(x\)ampere \(\text{A}\)amperometric detection method in electrochemical analysisamphipathic amphiphilic amphiprotic (solvent) ampholytes ampholytic polymer amphoteric amplification reaction amplitude of alternating current amplitude of alternating voltage anabolism anaerobe anaerobic anaesthetic analgesic analogue metabolism analogue to digital converter (pulse) analyte analytical function analytical instrument analytical intercomparison analytical portion analytical pyrolysis analytical quality control analytical radiochemistry analytical sample analytical solution analytical solution calorimetry analytical unit anation anchimeric assistance aneroid barometer Anger camera angle angle of observation angle of optical rotation \(\alpha\)angle strain angular distribution angular frequency \(\omega\)angular momentum \(L\)angular overlap model anhydrides anhydro bases anilides anils anion anion exchange anion exchanger anion radical anion-exchange polymer anionic polymer anionic polymerization anionotropic rearrangement anisometric anisotropy annelation annihilation in photochemistryannulation annulenes annulenylidenes anode anodic transfer coefficient anomeric effect anomers ansa compounds antagonism antagonist antarafacial anthelmint(h)ic anthocyanidins anthocyanins anti anti-Compton γ-ray spectrometer anti-Hammond effect anti-Markownikoff addition anti-Stokes shift anti-Stokes type radiation (fluorescence) anti-thixotropy antiaromatic compounds antiaromaticity antibiotic antibody antibonding molecular orbital anticholinergic anticircular elution in planar chromatographyanticlinal anticlined structures in polymersanticodon anticyclone in atmospheric chemistryantiferroelectric transition antiferromagnetic transition antigen antihelminth antimetabolite antimony–xenon lamp (arc) antimycotic antiparticle antiperiplanar antipodes antiprismo- antiresistant antiserum antisymmetry principle ap apex apex current apex potential aphicide apical (basal, equatorial) apicophilicity apo- in carotenoid nomenclatureapoenzyme apoprotein apoptosis apparent (quantity) apparent lifetime apparent viscosity of a liquidappearance energy appearance potential appearance temperature \(T_{\text{app}}\) in electrothermal atomizationapplied potential aprotic (solvent) aquagel aquation arachno- Archibald's method area of an electrode-solution interfacearea of interface area viscosity areic arene epoxides arene oxides arenes arenium ions arenols arenonium ions argon ion laser arithmetic mean aromatic aromatic photocycloaddition aromaticity arrester in atmospheric chemistryArrhenius A factor \(A\)Arrhenius energy of activation Arrhenius equation arsanes arsanylidenes arsanylium ions arsenides arsine oxides arsines arsinic acids arsinidenes arsinous acids arsonic acids arsonium compounds arsonous acids arsoranes artificial graphite artificial neural networks artificial radioactivity aryl cations aryl groups arylene groups aryne ascending elution in planar chromatographyash in atmospheric chemistryashing in analysisaspirator assay assay kit association association reaction in mass spectrometryassociative desorption associative ionization in mass spectrometryassociative surface reaction asym- asymmetric asymmetric carbon atom asymmetric centre asymmetric destruction asymmetric film asymmetric induction asymmetric membrane asymmetric photochemistry asymmetric synthesis asymmetric transformation asymmetry asymmetry potential of a glass electrodeatactic macromolecule atactic polymer atmosphere atmosphere of the earthatmospheric pressure ionization in mass spectrometryatom atom-atom polarizability atom-bond polarizability atom–molecule complex mechanism atomic charge atomic fluorescence atomic laser atomic mass constant atomic mass \(m_{\text{a}}\)atomic mass unit atomic number \(Z\)atomic orbital \(\psi\),\(\varphi\),\(\chi\)atomic ring-sector atomic spectral lines atomic symbol atomic units atomic weight atomization in analytical flame spectroscopyatomization surface temperature \(T_{\text{s}}\) in electrothermal atomizationatomize atomizer in analytical flame spectroscopyatropisomers attachment attenuance filter attenuance \(D\)attenuation attenuation coefficient atto attractive potential-energy surface attractive–mixed–repulsive classification attributable risk aufbau principle Auger effect Auger electron Auger electron spectroscopy Auger electron yield Auger yield autacoid auto-ionization in mass spectrometryautocatalytic reaction automation in analysisautomerization autophobicity autopoisoning in catalysisautoprotolysis autoprotolysis constant autoradiograph autoradiolysis auxiliary electrode auxochrome auxotrophy avalanche photodiode average current density average degree of polymerization average life in nuclear chemistryaverage rate of flow in polarographyAvogadro constant \(N_{\text{A}}\),\(L\)avoided crossing of potential-energy surfacesAvrami equation axial (equatorial) axial chirality axialite in polymer crystalsaxis of chirality axis of helicity aza-di-π-methane rearrangement azacarbenes azamines azanes azenes azides azimines azines azinic acids azlactones azo compounds azo imides azo ylides azomethine imides azomethine oxides azomethine ylides azomethines azonic acids azoxy compounds azylenes α (alpha), β (beta) α-addition α-cleavage α-decay α-effect α-elimination α-oxo carbenes α-particle π-adduct σ-adduct