Absorption processes, terms used

Certain features of light emission processes have been alluded to in Sect. 4.4.1. Fluorescence is light emission between states of the same multiplicity, whereas phosphorescence refers to emission between states of different multiplicities. The Franck-Condon principle governs the emission processes, as it does the absorption process. Vibrational overlap determines the relative intensities of different subbands. In the upper electronic state, one expects a quick relaxation and, therefore, a thermal population distribution, in the liquid phase and in gases at not too low a pressure. Because of the combination of the Franck-Condon principle and fast vibrational relaxation, the emission spectrum is always red-shifted. Therefore, oscillator strengths obtained from absorption are not too useful in determining the emission intensity. The theoretical radiative lifetime in terms of the Einstein coefficient, r = A-1, or (EA,)-1 if several lower states are involved,... 

Sorensen titration analy chem Titration with one of the Sorensen hydrogen-ion-concentration indicators. sor-an-san tT.tra-shon sorption phys chem A general term used to encompass the processes of adsorption, absorption, desorption, ion exchange, ion exclusion, ion retardation, chemisorption, and dialysis. sorp-shan )... 

Sorption Refers to adsorption and/or absorption. Some researchers use the generic term sorption to refer to a natural or artificial process where both adsorption and absorption may be involved or if adsorption and absorption cannot be distinguished. In particular, sorption is a treatment technology that primarily uses adsorption and/or absorption to remove contaminants from water, other liquids, or gases. 

Adsorption, absorption, and sorption are terms used to describe the uptake of a solute by another phase. Adsorption describes the concentration of a solute at the interface of two phases, while absorption describes the process when a solute is transferred from the bulk state of one phase into the bulk state of the other phase (Hassett and Banwart, 1989). The term sorption is used frequently in environmental situations to denote the uptake of a solute by a solid (soil or sediment or component of soil) without reference to a specific mechanism, or when the mechanism is uncertain. 

In another direction, words ending in -tion, such as absorption, reflection, radiation, transmission, and diffraction, are process terms. As such, they should not be used for the entity absorbed, radiated, or transmitted, nor for the corresponding measured values, such as absorptance, absorbance, reflectance, and transmittance. 

A common inconsistency is the coordinate use of acid and basic. It would seem that the first term should be acidic if the second is basic. Another example is the use of reflectometer and absorptiometer. As the process terms are reflection and absorption, it seems that the names of the instruments should be spelled consistently. Reflectometer has long been used. Absorptometer (or absorptimeter) is the obvious, consistent term. 

Disposition is the term used to describe the simultaneous effects of distribution and elimination, that is, the processes that occur subsequent to the absorption of a drug into the systemic circulation. The disposition of a drug is... 

Toxicokinetics is a term used for describing kinetic studies conducted in conjunction with toxicology evaluations (Di Carlo 1982) that deal with absorption, distribution, and elimination processes of chemicals present at concentrations that produce toxic effects. By monitoring the blood concentrations of the chemical and/or metabolites over time after administration by different routes, the test chemical s bioavailability and kinetic characteristics can be readily obtained. The data also permit the determination of the so-called linear dose range based on area under the plasma versus time curve and clearance or other related toxicokinetic parameters, as well as the prediction of possible bioaccumulation after multiple doses. Changes in kinetic parameters after multiple exposures... 

Opiates and opioid derivatives (a) delay the transit of intraluminal contents or (b) increase gut capacity, prolonging contact and absorption. Enkephalins, endogenous opioid substances, regulate fluid movement across the mucosa by stimulating absorptive processes. Limitations to the use of opiates include an addiction potential (a real concern with long-term use) and worsening of diarrhea in selected infectious diarrhea. 

The matrix element for the absorption process may now be expressed in terms of molecular tensors S , s follows, using the convention... 

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