Collision-induced absorption of O2 in the Herzberg continuum

Shardanand,; Rao, Arun D.

doi:10.1016/0022-4073(77)90122-4

Cited by 71 publications

(13 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This problem is typically dealt with by making absorption measurements at a series of relatively high pressures and then extrapolating to the low-pressure limit by using the assumption that the absorption has a known functional dependence on the 02 density. The various laboratory results are well summarized in a recent paper by Shardanand and Rao [1977]. This paper presents the calculation of the 02 and 03 absorption cross sections from an analysis of solar flux measurements obtained within the stratosphere between 20 and 40 km altitude.…”

Section: Laboratory Measurements Of the O2(35;g -) Dissociationmentioning

confidence: 99%

O₂ absorption cross sections (187–225 nm) from stratospheric solar flux measurements

Herman¹,

Mentall²

1982

J. Geophys. Res.

107

View full text Add to dashboard Cite

The absorption cross sections of molecular oxygen are calculated in the wavelength range from 187 to 230 nm from solar flux measurements obtained within the stratosphere. Within the Herzberg continuum wavelength region the molecular oxygen cross sections are found to be about 30% smaller than the laboratory results of Shardanand and Rao (1977) from 200 to 210 nm and about 50% smaller than those of Hasson and Nicholls (1971). At wavelengths longer than 210 nm the cross sections agree with those of Shardanand and Rao. The effective absorption cross sections of O2 in the Schumann‐Runge band region from 187 to 200 nm are calculated and compared to the empirical fit given by Allen and Frederick (1982). The calculated cross sections indicate that the transmissivity of the atmosphere may be underestimated by the use of the Allen and Frederick cross sections between 195 and 200 nm. The ozone column content between 30 and 40 km and the relative ozone cross sections are determined from the same solar flux data set. The calculated ozone absorption cross sections agree with those of Inn and Tanaka (1959) and Bass and Paur (1981) to within 3%.

show abstract

Section: Laboratory Measurements Of the O2(35;g -) Dissociationmentioning

confidence: 99%

O₂ absorption cross sections (187–225 nm) from stratospheric solar flux measurements

Herman¹,

Mentall²

1982

J. Geophys. Res.

107

View full text Add to dashboard Cite

show abstract

“…The dissociation of molecular oxygen by solar radiation between about 175 and 242 nm is the only important source for ozone in the stratosphere. This dissociation region contains the Schumann-Runge bands recently studied at high resolution by Yoshino et al [-1983-], continua underlying the $chumann-Runge bands, and the Herzberg continuum, which has been studied in the laboratory by several investigators [Shardanand and Rao, 1977;O•tawa, 1971;Hasson and Nicholls, 1971; Ditchburn and Youn•t, 1962-]. This absorption is extremely weak, cr < 10 -23 cm 2, and it is increased by biomolecular collisions between two oxygen molecules and also by collision with argon or with nitrogen [Shardanand, 1977[Shardanand, , 1978.…”

Section: Introductionmentioning

confidence: 99%

Oxygen absorption cross sections in the herzberg continuum and between 206 and 327 K

Johnston¹,

Paige²,

Yao³

1984

J. Geophys. Res.

View full text Add to dashboard Cite

The ultraviolet absorption cross sections for molecular oxygen have been determined for wavelengths between 205 and 225 nm, for temperatures between 206 and 327 K, and at a pressure from 100 to 750 torr. No temperature effect on the O2 cross sections was observed in the Herzberg continuum. It was necessary to separate the extremely weak O2 absorption from the stronger collision‐induced absorption. These experimental data and similar data by others were interpreted in terms of a theoretical expression for the shape of the Herzberg continuum absorption spectrum. The O2 absorption cross sections are in good agreement with the values measured in the stratosphere by Herman and Mentall (1982).

show abstract

“…These in situ determinations of a,,(h) give cross sections that are, in the region 193-205 nm, as low as or lower than the lowest previous laboratory values, which are those of Ogawa (8) and Shardanand and Rao (6). In the region 200-2 10 nm, Herman and Mentall (2) find cross-section values that are 72-86% of those of Shardanand and Rao (6). Frederick and Mentall (3) suggest values that are 85 -93% of those of Shardanand and Rao (6), while Anderson and Hall ( I ) derive an average value, for the 203-207 nm region, of 0.7(+0.2) X cm', which is about 80% as large as the laboratory values of Shardanand and Rao (6).…”

Section: -250mentioning

confidence: 84%

“…In the region 200-2 10 nm, Herman and Mentall (2) find cross-section values that are 72-86% of those of Shardanand and Rao (6). Frederick and Mentall (3) suggest values that are 85 -93% of those of Shardanand and Rao (6), while Anderson and Hall ( I ) derive an average value, for the 203-207 nm region, of 0.7(+0.2) X cm', which is about 80% as large as the laboratory values of Shardanand and Rao (6). In spite of their respective uncertainties, these three in situ The unsatisfactory status of measurements of the Herzberg continuum cross section has been discussed by Nicolet ( 12), Frederick ( 13).…”

Section: -250mentioning

confidence: 84%

Herzberg continuum cross section of oxygen in the wavelength region 193.5–204.0 nm and band oscillator strengths of the (0, 0) and (1, 0) Schumann–Runge bands

Cheung¹,

Yoshino²,

Parkinson³

et al. 1984

Can. J. Phys.

View full text Add to dashboard Cite

Reccivcd Junc 6. I984Cross scctions of oxygcn at 300 K havc bccn obtaincd from photoabsorption mcasurcrncnts at various prcssures, from 50 to 760 Torr ( 1 Torr = 133.3 Pa). at wavelength intervals of 0.0002 nm throughout thc rcgion 193.5-204.0 nin with a 6.65-111 photoelectric scanning spectromctcr equipped with a 2400 linc/min grating and having an instrumental full width at half maximum of 0.0013 nm. Thc spcctral fcatures contributing to absorption in this rcgion are thc discrctc lincs of somc Schumann-Rungc bands and underlying dissociation continua consisting of thc weak Hcrzbcrg continuum of 0: and a pressure dcpendcnt continuum involving two molcculcs of 02. Analysis of the prcssurc dcpcndcncc of the total continuun~ cross section in window regions bctwccn thc discrcte lincs yiclds thc Hcrzbcrg continuum cross scction, which dccreascs monotonically from 1.4 X lo-' cm' at 193.58 nm to 5.1 X 1 0 " cm'at 204.06 nm. At all wavclcngths in this rcgion. our valucs of thc Hcrzbcrg continuum cross scction arc smallcr than previous laboratory values. much smaller than thc valucs uscd in many photochemical stratospheric modcls, and consistent with rccent it1 .sit~c stratosphcric cross-scction mcasurcmcnts. Thc acccptancc of reduced Hcrzbcrg continuum cross scctions significantly affccts photochemical modelling prcdictions. Band oscillator strcngths f ( 0 . 0 ) = 2.95 X 10 'I' and f ( I , 0) = 3.13 x I0 -" of thc (0,0) and ( I . 0) Schumann-Rungc bands havc bccn dctcrmincd by dircct numerical intcgration of the mcasurcd discrctc cross scction rcmaining aftcs subtraction of thc continua from thc total cross section. Improved wavcnumbcr mcasuremcnts of thc (0.0) and (2. 1 ) Schumann-Rungc bands arc givcn.Les scctions cfficaces dc I'oxygitnc ii 300 K ont dtd obtcnucs par dcs mcsurcs dc photoabsorption i~ diffdrcntcs pressions, dc 50 ii 760 Torr ( I Torr = 133.3 Pa), pour dcs intcrvalles dc longucur d'ondc dc 0.0002 nm dans la rdgion dc 193.5-204,O nm. au moycn d'un spcctromittrc photo-dlcctriquc i balayagc pourvu d'un rdscau ii 2400 ligncs/mm ct possddant unc largcur totalc instrumcntale dc 0,0013 nm ii dcmi-intcnsitd. Lcs contributions ii I'absorption dans ccttc rdgion sont Ics raics discrktes dc certaincs bandcs Schumann-Rungc ct Ics continua dc dissociation sous-jaccnts comprcnant Ic faible continuum dc Hcrzberg pour 0' ct un continuum ddpcndant dc la prcssion nicttant cn jcu dcux moldculcs dc 02. L'analysc dc la ddpcndancc sclon la prcssion dc la scction cfficacc totalc du continuum dans Ics fcnEtrcs spcctralcs cntrc Ics raics discrktcs fournit la scction cfficacc du continuum dc Hcrzbcrg, qui ddcroit dc fagon monotonc dc 1,4 X lo-'' cm' pour 193,58 nnl h 5.1 X 10 " em' pour 204,06 nm. Pour toutcs Ics longueurs d'ondc, dans ccttc rdgion, nos valcurs dc la scction cfficacc du continuum dc Hcrzbcrg sont plus pctitcs que Ics valcurs cxpdrimcntalcs dc laboratoirc obtcnucs prdccdemrncnt. bcaucoup plus pctitcs quc Ics valcurs utilisdcs dans dc nombrcux modclcs photo-chimiqucs pour la stratosphere, et cn accord avcc dcs mcsu...

show abstract

Collision-induced absorption of O2 in the Herzberg continuum

Cited by 71 publications

References 22 publications

O₂ absorption cross sections (187–225 nm) from stratospheric solar flux measurements

O₂ absorption cross sections (187–225 nm) from stratospheric solar flux measurements

Oxygen absorption cross sections in the herzberg continuum and between 206 and 327 K

Herzberg continuum cross section of oxygen in the wavelength region 193.5–204.0 nm and band oscillator strengths of the (0, 0) and (1, 0) Schumann–Runge bands

Contact Info

Product

Resources

About

Collision-induced absorption of O2 in the Herzberg continuum

Cited by 71 publications

References 22 publications

O2 absorption cross sections (187–225 nm) from stratospheric solar flux measurements

O2 absorption cross sections (187–225 nm) from stratospheric solar flux measurements

Oxygen absorption cross sections in the herzberg continuum and between 206 and 327 K

Herzberg continuum cross section of oxygen in the wavelength region 193.5–204.0 nm and band oscillator strengths of the (0, 0) and (1, 0) Schumann–Runge bands

Contact Info

Product

Resources

About

O₂ absorption cross sections (187–225 nm) from stratospheric solar flux measurements

O₂ absorption cross sections (187–225 nm) from stratospheric solar flux measurements