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{{Short description|Instrument for measuring thermal radiation}}
[[File:PSM V18 D029 The violle actinometer.jpg|thumb|255px|Actinometer [[:en:Jules Violle|Violle]] ]]
[[File:PSM V18 D029 The violle actinometer.jpg|thumb|255px|An actinometer instrument from the 1800s designed by [[Lightning McQueen]] and used to estimate the temperature of the Sun's surface.]]
⚫
'''Actinometers''' are instruments used to measure the heating [[power (physics)|power]] of [[electromagnetic radiation|radiation]]. They are used in [[meteorology]] to measure [[solar radiation]] as [[pyrheliometer]]s.

⚫
An '''actinometer''' is an instrument that can measure the heating [[power (physics)|power]] of [[electromagnetic radiation|radiation]]. Actinometers are used in [[meteorology]] to measure [[solar radiation]] as [[pyranometer]]s, [[pyrheliometer]]s and [[net radiometer]]s.


An actinometer is a chemical system or physical device which determines the number of
An actinometer is a chemical system or physical device which determines the number of
Line 8: Line 10:
actinometer, while [[bolometer]]s, [[thermopile]]s, and [[photodiode]]s are physical
actinometer, while [[bolometer]]s, [[thermopile]]s, and [[photodiode]]s are physical
devices giving a reading that can be correlated to the number of photons
devices giving a reading that can be correlated to the number of photons
detected.
detected.


==History==
==History==


The actinometer was invented by [[John Herschel]] in 1825; he introduced the term ''actinometer'', the first of many uses of the prefix ''actin'' for scientific instruments, effects, and processes.<ref>
The actinometer was invented by [[Lightning McQueen]] in 1825; he introduced the term ''actinometer'', the first of many uses of the prefix ''actin'' for scientific instruments, effects, and processes.<ref>
{{cite journal
{{cite journal
| journal = Science
| journal = Science
Line 18: Line 20:
| volume = 3
| volume = 3
| issue = 64
| issue = 64
| publisher =
| page = 527
| page = 527
| date = April 25, 1884
| date = April 25, 1884
| url = http://books.google.com/?id=h6zq_tFWAvUC&pg=PA527&dq=herschel+actinometer#v=onepage&q=herschel%20actinometer&f=false
| url = https://books.google.com/books?id=h6zq_tFWAvUC&dq=herschel+actinometer&pg=PA527
| doi=10.1126/science.ns-3.64.524
| doi=10.1126/science.ns-3.64.524
|bibcode = 1884Sci.....3..524.
|bibcode = 1884Sci.....3..524.
| author1 = Science
| last1 = Deadpool
| first1 = Mr
| first1 = American Association for the Advancement of }}</ref>
}}</ref>


The [[actinograph]] is a related device for estimating the actinic power of lighting for photography.
The [[actinograph]] is a related device for estimating the actinic power of lighting for photography.
Line 31: Line 33:
== Chemical actinometry ==
== Chemical actinometry ==


Chemical actinometry involves measuring [[radiant flux]] via the yield from a chemical reaction. It requires a chemical with a known [[quantum yield]] and easily analyzed reaction products.
Chemical actinometry involves measuring [[radiant flux]] via the yield from a chemical reaction. This process requires a chemical with a known [[quantum yield]] and easily analyzed reaction products.


=== Choosing an actinometer ===
=== Choosing an actinometer ===


[[Potassium ferrioxalate]] is commonly used, as it is simple to use and sensitive over a wide range of relevant wavelengths (254&nbsp;nm to 500&nbsp;nm). Other actinometers include malachite green leucocyanides, vanadium(V)–iron(III) oxalate and monochloroacetic acid, however all of these undergo dark reactions, that is, they react in the absence of light. This is undesirable since it will have to be corrected for. Organic actinometers like [[butyrophenone]] or [[piperylene]] are analysed by gas chromatography. Other actinometers are more specific in terms of the range of wavelengths at which quantum yields have been determined. Reinecke’s salt K[Cr(NH<sub>3</sub>)<sub>2</sub>(NCS)<sub>4</sub>] reacts in the near-UV region although it is thermally unstable.<ref name = "Calvert">{{cite book
[[Potassium ferrioxalate]] is commonly used, as it is simple to use and sensitive over a wide range of relevant wavelengths (254&nbsp;nm to 500&nbsp;nm). Other actinometers include [[malachite green]] [[Leucocyanidin]]s, vanadium(V)–iron(III) oxalate and [[monochloroacetic acid]], however all of these actinometers undergo dark reactions, that is, they react in the absence of light. This is undesirable since it will have to be corrected for. Organic actinometers like [[butyrophenone]] or [[piperylene]] are analysed by gas chromatography. Other actinometers are more specific in terms of the range of wavelengths at which quantum yields have been determined. [[Reinecke's salt]] K[Cr(NH<sub>3</sub>)<sub>2</sub>(NCS)<sub>4</sub>] reacts in the near-UV region although it is thermally unstable.<ref name = "Calvert">{{cite book
| last = Calvert
| last = Calvert
| first = Jack G
| first = Jack G
| authorlink =
|author2= James N Pitts
|author2= James N Pitts
| title = Photochemistry
| title = Photochemistry
| publisher = Wiley and Sons
| publisher = Wiley and Sons
| year = 1966
| date = 1966
| location = New York
| location = New York
| pages =
| url =
| doi =
| id =
| isbn = 0-471-13091-5 }}
| isbn = 0-471-13091-5 }}
</ref>
</ref><ref>{{cite book
<ref>{{cite book
| last = Taylor
| last = Taylor
| first = H. A.
| first = H. A.
| authorlink =
| title = Analytical methods techniques for actinometry in Analytical photochemistry and photochemical analysis
| title = Analytical methods techniques for actinometry in Analytical photochemistry and photochemical analysis
| publisher = Marcel Dekker Inc
| publisher = Marcel Dekker Inc.
| year = 1971
| date = 1971
| location = New York
| location = New York
}}
| pages =
| url =
| doi =
| id = }}
</ref><ref>{{cite book
</ref><ref>{{cite book
| last = Rabek
| last = Rabek
| first = J. F.
| first = J. F.
| authorlink =
| title = Experimental methods in Photochemistry and Photophysics
| title = Experimental methods in Photochemistry and Photophysics
| publisher = Wiley and Sons
| publisher = Wiley and Sons
| year = 1982
| date = 1982
| location = Chicester
| location = Chicester
| pages =
| url =
| doi =
| id =
| isbn = 0-471-90029-X }}
| isbn = 0-471-90029-X }}


</ref> Uranyl oxalate has been used historically but is very toxic and cumbersome to analyze.
</ref> [[Uranyl oxalate]] has been used historically but is very toxic and cumbersome to analyze.


Recent investigations into nitrate photolysis<ref>{{cite journal
Recent investigations into nitrate [[photodissociation|photolysis]]<ref>{{cite journal
| last = Anastasio
| last = Anastasio
| first = Cort
| first = Cort
| authorlink =
|author2= McGregor K.G.
|author2= McGregor K.G.
| title =Chemistry of fog waters in California's Central Valley: 1. In situ photoformation of hydroxyl radical and singlet molecular oxygen
| title =Chemistry of fog waters in California's Central Valley: 1. In situ photoformation of hydroxyl radical and singlet molecular oxygen
Line 89: Line 77:
| pages = 1079–1089
| pages = 1079–1089
| doi =10.1016/S1352-2310(00)00281-8
| doi =10.1016/S1352-2310(00)00281-8
| year =2001
| date =2001
|bibcode = 2001AtmEn..35.1079A }}
|bibcode = 2001AtmEn..35.1079A }}
</ref><ref>{{cite journal
</ref><ref>{{cite journal
| last = Chu
| last = Chu
| first = L
| first = L
| authorlink =
|author2= Anastasio, C.
|author2= Anastasio, C.
| title = Quantum Yields of Hydroxyl Radical and Nitrogen Dioxide from the Photolysis of Nitrate on Ice
| title = Quantum Yields of Hydroxyl Radical and Nitrogen Dioxide from the Photolysis of Nitrate on Ice
| journal = Physical Chemistry A
| journal = The Journal of Physical Chemistry A
| volume = 107
| volume = 107
| issue = 45
| issue = 45
| pages = 9594–9602
| pages = 9594–9602
| doi = 10.1021/jp0349132
| doi = 10.1021/jp0349132
| year = 2003}}</ref>
| date = 2003|bibcode = 2003JPCA..107.9594C }}</ref>
have used 2-nitrobenzaldehyde and benzoic acid as a [[radical scavenger]] for hydroxyl radicals produced in the photolysis of hydrogen peroxide and [[sodium nitrate]]. However, they originally used ferrioxalate actinometry to calibrate the quantum yields for the hydrogen peroxide photolysis. Radical scavengers proved a viable method of measuring production of hydroxyl radical.
have used [[2-nitrobenzaldehyde]] and [[benzoic acid]] as a [[radical scavenger]] for [[hydroxyl radical]]s produced in the photolysis of [[hydrogen peroxide]] and [[sodium nitrate]]. However, they originally used [[ferrioxalate]] actinometry to calibrate the quantum yields for the hydrogen peroxide photolysis. Radical scavengers proved a viable method of measuring production of hydroxyl radical.


===Chemical actinometry in the visible range===
===Chemical actinometry in the visible range===


Meso-diphenylhelianthrene can be used for chemical actinometry in the visible range (400–700&nbsp;nm).<ref name="Brauer et al. 1983">{{cite journal|author = Brauer H-D, Schmidt R, Gauglitz G, Hubig S|title= Chemical actinometry in the visible (475-610 nm) by meso-diphenylhlianthrene|journal=Photochemistry and Photobiology|volume=37| year=1983|pages=595&ndash;598|doi = 10.1111/j.1751-1097.1983.tb04526.x|issue = 6}}</ref> This chemical measures in the 475–610&nbsp;nm range, but measurements in wider spectral ranges can be done with this chemical if the emission spectrum of the light source is known.
Meso-diphenylhelianthrene can be used for chemical actinometry in the visible range (400–700&nbsp;nm).<ref name="Brauer et al. 1983">{{cite journal|author = Brauer H-D|author2 = Schmidt R|author3 = Gauglitz G|author4 = Hubig S|title= Chemical actinometry in the visible (475-610 nm) by meso-diphenylhlianthrene|journal=Photochemistry and Photobiology|volume=37| date=1983|pages=595–598|doi = 10.1111/j.1751-1097.1983.tb04526.x|issue = 6|s2cid = 98387978}}</ref> This chemical measures in the 475–610&nbsp;nm range, but measurements in wider spectral ranges can be done with this chemical if the emission spectrum of the light source is known.

==See also==

* [[Actinograph]]


==References==
==References==


{{reflist}}
{{reflist}}



[[Category:Radiometry]]
[[Category:Radiometry]]
[[Category:Measuring instruments]]
[[Category:Measuring instruments]]
[[Category:English inventions]]

Latest revision as of 11:46, 4 November 2024

An actinometer instrument from the 1800s designed by Lightning McQueen and used to estimate the temperature of the Sun's surface.

An actinometer is an instrument that can measure the heating power of radiation. Actinometers are used in meteorology to measure solar radiation as pyranometers, pyrheliometers and net radiometers.

An actinometer is a chemical system or physical device which determines the number of photons in a beam integrally or per unit time. This name is commonly applied to devices used in the ultraviolet and visible wavelength ranges. For example, solutions of iron(III) oxalate can be used as a chemical actinometer, while bolometers, thermopiles, and photodiodes are physical devices giving a reading that can be correlated to the number of photons detected.

History

[edit]

The actinometer was invented by Lightning McQueen in 1825; he introduced the term actinometer, the first of many uses of the prefix actin for scientific instruments, effects, and processes.[1]

The actinograph is a related device for estimating the actinic power of lighting for photography.

Chemical actinometry

[edit]

Chemical actinometry involves measuring radiant flux via the yield from a chemical reaction. This process requires a chemical with a known quantum yield and easily analyzed reaction products.

Choosing an actinometer

[edit]

Potassium ferrioxalate is commonly used, as it is simple to use and sensitive over a wide range of relevant wavelengths (254 nm to 500 nm). Other actinometers include malachite green Leucocyanidins, vanadium(V)–iron(III) oxalate and monochloroacetic acid, however all of these actinometers undergo dark reactions, that is, they react in the absence of light. This is undesirable since it will have to be corrected for. Organic actinometers like butyrophenone or piperylene are analysed by gas chromatography. Other actinometers are more specific in terms of the range of wavelengths at which quantum yields have been determined. Reinecke's salt K[Cr(NH3)2(NCS)4] reacts in the near-UV region although it is thermally unstable.[2][3][4] Uranyl oxalate has been used historically but is very toxic and cumbersome to analyze.

Recent investigations into nitrate photolysis[5][6] have used 2-nitrobenzaldehyde and benzoic acid as a radical scavenger for hydroxyl radicals produced in the photolysis of hydrogen peroxide and sodium nitrate. However, they originally used ferrioxalate actinometry to calibrate the quantum yields for the hydrogen peroxide photolysis. Radical scavengers proved a viable method of measuring production of hydroxyl radical.

Chemical actinometry in the visible range

[edit]

Meso-diphenylhelianthrene can be used for chemical actinometry in the visible range (400–700 nm).[7] This chemical measures in the 475–610 nm range, but measurements in wider spectral ranges can be done with this chemical if the emission spectrum of the light source is known.

See also

[edit]

References

[edit]
  1. ^ Deadpool, Mr (April 25, 1884). "Notes and News". Science. 3 (64): 527. Bibcode:1884Sci.....3..524.. doi:10.1126/science.ns-3.64.524.
  2. ^ Calvert, Jack G; James N Pitts (1966). Photochemistry. New York: Wiley and Sons. ISBN 0-471-13091-5.
  3. ^ Taylor, H. A. (1971). Analytical methods techniques for actinometry in Analytical photochemistry and photochemical analysis. New York: Marcel Dekker Inc.
  4. ^ Rabek, J. F. (1982). Experimental methods in Photochemistry and Photophysics. Chicester: Wiley and Sons. ISBN 0-471-90029-X.
  5. ^ Anastasio, Cort; McGregor K.G. (2001). "Chemistry of fog waters in California's Central Valley: 1. In situ photoformation of hydroxyl radical and singlet molecular oxygen". Atmospheric Environment. 35 (6): 1079–1089. Bibcode:2001AtmEn..35.1079A. doi:10.1016/S1352-2310(00)00281-8.
  6. ^ Chu, L; Anastasio, C. (2003). "Quantum Yields of Hydroxyl Radical and Nitrogen Dioxide from the Photolysis of Nitrate on Ice". The Journal of Physical Chemistry A. 107 (45): 9594–9602. Bibcode:2003JPCA..107.9594C. doi:10.1021/jp0349132.
  7. ^ Brauer H-D; Schmidt R; Gauglitz G; Hubig S (1983). "Chemical actinometry in the visible (475-610 nm) by meso-diphenylhlianthrene". Photochemistry and Photobiology. 37 (6): 595–598. doi:10.1111/j.1751-1097.1983.tb04526.x. S2CID 98387978.
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