ASTM E131-10
(Terminology)Standard Terminology Relating to Molecular Spectroscopy
Standard Terminology Relating to Molecular Spectroscopy
SCOPE
1.1 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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Designation: E131 − 10
StandardTerminology Relating to
1, 2
Molecular Spectroscopy
This standard is issued under the fixed designation E131; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
refractive effects, if present, and that attenuation by scattering is small
1. Scope
comparedwithattenuationbyabsorption.Apparentdeviationsfromthe
1.1 The values stated in SI units are to be regarded as
absorption laws (see absorptivity) are due to inability to measure
standard. No other units of measurement are included in this
exactly the true transmittance or to know the exact concentration of an
standard.
absorbing substance.
absorption band—a region of the absorption spectrum in
2. Referenced Documents
which the absorbance passes through a maximum.
3
2.1 ASTM Standards:
E135Terminology Relating to Analytical Chemistry for absorption coefficient, α—a measure of absorption of radiant
Metals, Ores, and Related Materials
energy from an incident beam as it traverses an absorbing
−αb
E168Practices for General Techniques of Infrared Quanti- medium according to Bouguer’s law, P/P = e .
o
tative Analysis
DISCUSSION—In IRS, α is a measure of the rate of absorption of
E204Practices for Identification of Material by Infrared energy from the evanescent wave.
Absorption Spectroscopy, Using the ASTM Coded Band
absorption parameter, a—the relative reflection loss per
and Chemical Classification Index
reflection that results from the absorption of radiant energy
E284Terminology of Appearance
at a reflecting surface: a=1− R, and R=the reflected
E386Practice for Data Presentation Relating to High-
fraction of incident radiant power.
Resolution Nuclear Magnetic Resonance (NMR) Spec-
troscopy
absorption spectrum—a plot, or other representation, of
E456Terminology Relating to Quality and Statistics
absorbance, or any function of absorbance, against
4
2.2 Other Documents: wavelength, or any function of wavelength.
ISOGuide30–1981(E)Terms and definitions used in con-
absorptivity, a—theabsorbancedividedbytheproductofthe
nections with reference materials
concentration of the substance and the sample pathlength,
a = A/bc. The units of b and c shall be specified.
3. Terminology
DISCUSSION—1—The recommended unit for b is the centimetre. The
absorbance, A—the logarithm to the base 10 of the reciprocal
recommended unit for c is kilogram per cubic metre. Equivalent units
3 3
of the transmittance, (T). are g/dm , g/L, or mg/cm .
A 5 log 1/T 52log T (1)
~ !
10 10 DISCUSSION—2—The equivalent IUPAC term is “specific absorption
DISCUSSION—In practice the observed transmittance must be substi-
coefficient.”
tuted for T.Absorbance expresses the excess absorption over that of a
specified reference or standard. It is implied that compensation has absorptivity, molar, ε—the product of the absorptivity, a, and
been effected for reflectance losses, solvent absorption losses, and
the molecular weight of the substance.
DISCUSSION—The equivalent IUPAC term is “molar absorption coef-
ficient.”
1
This terminology is under the jurisdiction of ASTM Committee E13 on
Molecular Spectroscopy and Separation Science and is the direct responsibility of
acceptance angle, n—for an optical fiber,themaximumangle,
Subcommittee E13.94 on Terminology.
measuredfromthelongitudinalaxisorcenterlineofthefiber
Current edition approved March 1, 2010. Published April 2010. Originally
to an incident ray, within which the ray will be accepted for
approved in 1957. Last previous edition approved in 2005 as E131–05. DOI:
10.1520/E0131-10.
transmission along the fiber by total internal reflection.
2
Forotherdefinitionsrelatingtonuclearmagneticresonance,seePracticeE386.
DISCUSSION—If the incidence angle exceeds the acceptance angle,
optical power in the incident ray will be coupled into leaky modes or
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
rays, or lost by scattering, diffusion, or absorption in the cladding. For
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
a cladded step-index fiber in the air, the sine of the acceptance angle is
Standards volume information, refer to the standard’s Document Summary page on
givenbythesquarerootofthedifferenceofthesquaresoftherefractive
the ASTM website.
4
indexes of the fiber core and the cladding, that is, by the relation as
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. follows:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:E131–05 Designation:E131–10
Standard Terminology Relating to
,
1 2
Molecular Spectroscopy
This standard is issued under the fixed designation E131; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
2. Referenced Documents
1.1
3
2.1 ASTM Standards:
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E168 Practices for General Techniques of Infrared Quantitative Analysis
E204 PracticesforIdentificationofMaterialbyInfraredAbsorptionSpectroscopy,UsingtheASTMCodedBandandChemical
Classification Index
E284 Terminology of Appearance
E386 Practice for Data Presentation Relating to High-Resolution Nuclear Magnetic Resonance (NMR) Spectroscopy
E456 Terminology Relating to Quality and Statistics
1.2 Other Documents:
4
2.2 Other Documents:
ISOGuide30–1981(E) Terms and definitions used in connections with reference materials
2.
3. Terminology
absorbance, A—the logarithm to the base 10 of the reciprocal of the transmittance, (T).
(1) A 5log10~1/T!52log10T
DISCUSSION—In practice the observed transmittance must be substituted for T.Absorbance expresses the excess absorption over that of a specified
reference or standard. It is implied that compensation has been effected for reflectance losses, solvent absorption losses, and refractive effects, if
present, and that attenuation by scattering is small compared with attenuation by absorption. Apparent deviations from the absorption laws (see
absorptivity) are due to inability to measure exactly the true transmittance or to know the exact concentration of an absorbing substance.
absorption band—a region of the absorption spectrum in which the absorbance passes through a maximum.
absorption coefficient, a—a measure of absorption of radiant energy from an incident beam as it traverses an absorbing medium
−ab
according to Bouguer’s law, P/P = e .
o
DISCUSSION—In IRS, a is a measure of the rate of absorption of energy from the evanescent wave.
absorptionparameter, a—therelativereflectionlossperreflectionthatresultsfromtheabsorptionofradiantenergyatareflecting
surface:a=1− R, and R=the reflected fraction of incident radiant power.
absorption spectrum—a plot, or other representation, of absorbance, or any function of absorbance, against wavelength, or any
function of wavelength.
1
This terminology is under the jurisdiction ofASTM Committee E13 on Molecular Spectroscopy and Separation Science and is the direct responsibility of Subcommittee
E13.94 on Terminology.
Current edition approved Dec. 12, 2005. Published September 2005. Originally approved in 1957. Last previous edition approved in 2002 as E131–02. DOI:
10.1520/E0131-05.
Current edition approved March 1, 2010. Published April 2010. Originally approved in 1957. Last previous edition approved in 2005 as E131–05. DOI:
10.1520/E0131-10.
2
For other definitions relating to nuclear magnetic resonance, see Practice E386.
3
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E131–10
absorptivity, a—theabsorbancedividedbytheproductoftheconcentrationofthesubstanceandthesamplepathlength, a = A/bc.
The units of b and c shall be specified.
3
DISCUSSION—1—Therecommendedunitfor bisthecentimetre.Therecommendedunitfor ciskilogrampercubicmetre.Equivalentunitsareg/dm ,
3
g/L, or mg/cm .
DISCUSSION—2—The equivalent IUPAC term is “specific absorption coefficient.”
absorptivity, molar, ´—the product of the absorptivity, a, and the molecular weight of the substance.
DISCUSSION—The equivalent IUPAC term is “molar absorption coefficient.”
acceptance angle, n—for an optical fiber, the maximum angle, measured from the longitudinal axis or centerline of the fiber to
an incident ray, within which the ray will be accepted for transmission
...
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