View in EDS

Deviations from the Beer–Lambert Approximation Investigated Using Two-Dimensional Correlation Infrared Spectroscopy.

Saved in:
Bibliographic Details
Title: Deviations from the Beer–Lambert Approximation Investigated Using Two-Dimensional Correlation Infrared Spectroscopy.
Authors: Mayerhöfer, Thomas G.1,2 (AUTHOR) Thomas.Mayerhoefer@leibniz-ipht.de, Pahlow, Susanne1 (AUTHOR), Hübner, Uwe1 (AUTHOR), Popp, Jürgen1,2 (AUTHOR)
Source: Applied Spectroscopy. Jun2026, Vol. 80 Issue 6, p604-613. 10p.
Subjects: Beer-Lambert law, Optical interference, Infrared spectroscopy, Spectrum analysis, Polymethylmethacrylate, Electromagnetic theory
Abstract: Two-dimensional correlation spectroscopy (2D-COS) is a highly sensitive technique for detecting deviations from the Beer–Lambert approximation through asynchronous spectra. In this study, we apply 2D-COS to examine such deviations in the context of this approximation. While conventional molecular IR spectroscopy literature suggests a linear correlation between absorbance, molar concentration, and sample thickness, a more rigorous analysis, supported by electromagnetic theory, demonstrates that this assumption does not hold, even under ideal conditions. As a result, disproportionate spectral changes, caused by interference effects, give rise to distinct patterns in asynchronous 2D-COS IR spectra. To illustrate this, we investigate the thickness dependence of absorbance in poly(methyl methacrylate) (PMMA) layers deposited on calcium fluoride (CaF2) and Si. Our findings reveal systematic variations not only in absorbance values but also in band shapes and peak positions. 2D-COS emerges as a powerful tool for identifying and analyzing these patterns. [ABSTRACT FROM AUTHOR]
Copyright of Applied Spectroscopy is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
FullText Text:
  Availability: 0
Header DbId: egs
DbLabel: Engineering Source
An: 194446461
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Deviations from the Beer–Lambert Approximation Investigated Using Two-Dimensional Correlation Infrared Spectroscopy.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Mayerhöfer%2C+Thomas+G%2E%22">Mayerhöfer, Thomas G.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> Thomas.Mayerhoefer@leibniz-ipht.de</i><br /><searchLink fieldCode="AR" term="%22Pahlow%2C+Susanne%22">Pahlow, Susanne</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Hübner%2C+Uwe%22">Hübner, Uwe</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Popp%2C+Jürgen%22">Popp, Jürgen</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Applied+Spectroscopy%22">Applied Spectroscopy</searchLink>. Jun2026, Vol. 80 Issue 6, p604-613. 10p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Beer-Lambert+law%22">Beer-Lambert law</searchLink><br /><searchLink fieldCode="DE" term="%22Optical+interference%22">Optical interference</searchLink><br /><searchLink fieldCode="DE" term="%22Infrared+spectroscopy%22">Infrared spectroscopy</searchLink><br /><searchLink fieldCode="DE" term="%22Spectrum+analysis%22">Spectrum analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Polymethylmethacrylate%22">Polymethylmethacrylate</searchLink><br /><searchLink fieldCode="DE" term="%22Electromagnetic+theory%22">Electromagnetic theory</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Two-dimensional correlation spectroscopy (2D-COS) is a highly sensitive technique for detecting deviations from the Beer–Lambert approximation through asynchronous spectra. In this study, we apply 2D-COS to examine such deviations in the context of this approximation. While conventional molecular IR spectroscopy literature suggests a linear correlation between absorbance, molar concentration, and sample thickness, a more rigorous analysis, supported by electromagnetic theory, demonstrates that this assumption does not hold, even under ideal conditions. As a result, disproportionate spectral changes, caused by interference effects, give rise to distinct patterns in asynchronous 2D-COS IR spectra. To illustrate this, we investigate the thickness dependence of absorbance in poly(methyl methacrylate) (PMMA) layers deposited on calcium fluoride (CaF2) and Si. Our findings reveal systematic variations not only in absorbance values but also in band shapes and peak positions. 2D-COS emerges as a powerful tool for identifying and analyzing these patterns. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Applied Spectroscopy is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=194446461
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1177/00037028251368394
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 10
        StartPage: 604
    Subjects:
      – SubjectFull: Beer-Lambert law
        Type: general
      – SubjectFull: Optical interference
        Type: general
      – SubjectFull: Infrared spectroscopy
        Type: general
      – SubjectFull: Spectrum analysis
        Type: general
      – SubjectFull: Polymethylmethacrylate
        Type: general
      – SubjectFull: Electromagnetic theory
        Type: general
    Titles:
      – TitleFull: Deviations from the Beer–Lambert Approximation Investigated Using Two-Dimensional Correlation Infrared Spectroscopy.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Mayerhöfer, Thomas G.
      – PersonEntity:
          Name:
            NameFull: Pahlow, Susanne
      – PersonEntity:
          Name:
            NameFull: Hübner, Uwe
      – PersonEntity:
          Name:
            NameFull: Popp, Jürgen
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 06
              Text: Jun2026
              Type: published
              Y: 2026
          Identifiers:
            – Type: issn-print
              Value: 00037028
          Numbering:
            – Type: volume
              Value: 80
            – Type: issue
              Value: 6
          Titles:
            – TitleFull: Applied Spectroscopy
              Type: main
ResultId 1