Fourier-transform photoacoustic spectroscopy: a more complete method for quantitative analysis

1986 ◽  
Vol 64 (9) ◽  
pp. 1081-1085 ◽  
Author(s):  
M. Choquet ◽  
G. Rousset ◽  
L. Bertrand
Keyword(s):  
Absorption Spectrum ◽  
Fourier Transform ◽  
Quantitative Analysis ◽  
Photoacoustic Spectroscopy ◽  
Photoacoustic Signal ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Asbestos Fibers ◽  
Fourier Transform Spectra ◽  
Signal Saturation

Strong absorption bands of photoacoustic Fourier-transform spectra are often truncated relative to weaker bands owing to signal saturation. To correct this problem, we propose processing both the phase and the amplitude information in the photoacoustic signal. Under certain conditions, easily fulfilled in typical experiments, we are able to calculate the absolute absorption spectrum from the photoacoustic data. Experimental results are given for asbestos fibers (chrysotile).

scholarly journals The absorption spectra of conjugated dienes in the vacuum ultra-violet (1)

1940 ◽  
Vol 174 (957) ◽  
pp. 220-234 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Ultra Violet ◽  
Conjugated Dienes ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Lennard Jones ◽  
Vacuum Ultra Violet

Butadiene is important as the simplest example of resonance between two conjugated double bonds. The comparison of its ultra-violet absorption spectrum with that of ethylene might be expected to give some indication of the way the π electrons of the molecule are affected by the resonance. The electronic structures of a number of molecules for which resonance is important have been worked out theoretically by Hückel (1935), Lennard- Jones (1937), Sklar (1937) and Mulliken (1939 a and b ). The purpose of the present work is to obtain spectroscopic data with which the theoretical expectations can be compared. As most of the strong absorption bands of these molecules occur at wave-lengths less than 2000 A, the investigation falls naturally into the region of vacuum spectroscopy.

Application of photoacoustics to biology: some specific systems and methods

1986 ◽  
Vol 64 (9) ◽  
pp. 1132-1135 ◽  
Author(s):  
D. Balasubramanian ◽  
Ch. Mohan Rao
Keyword(s):  
Fourier Transform ◽  
Photoacoustic Spectroscopy ◽  
Biological Systems ◽  
Depth Profiling ◽  
Photoacoustic Signal ◽  
Mirage Effect ◽  
Photoacoustic Spectra ◽  
New Methods

A recent review of applications of photoacoustic spectroscopy to biological systems is presented. Examples of chromophore studies by photoacoustic spectroscopy show that a good correlation is possible between their presence or interactions and the photoacoustic spectra. Emphasis is placed on new interpretations of the photoacoustic signal as well as new methods such as depth profiling, the mirage effect, and Fourier-transform photoacoustic spectroscopy.

The Absorption Behavior of Water and Some Organic Liquids in the Near Infrared Studied by Photoacoustic Spectroscopy

1984 ◽  
Vol 39 (12) ◽  
pp. 1242-1249 ◽  
Author(s):  
U. Haas ◽  
H. Seiler
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Near Infrared ◽  
Modulation Frequency ◽  
Incident Light ◽  
Photoacoustic Signal ◽  
Liquid Structure ◽  
Organic Liquids ◽  
Absorption Bands ◽  
Expected Frequency ◽  
Hydroxyl Absorption

The optical absorption of water and some organic liquids [CH3OH, CH3OD, CD3OD, C2H5OH, C4H9OH, (CH3)2CO, (C2H5)2O and C6H6] has been investigated in the near infrared by photoacoustic spectroscopy. Characteristical absorption bands of combinations and overtones of strong infrared fundamental vibrations are observed and can be used for qualitative analysis of these liquids. The amplitude of the photoacoustic signal shows an f-1-dependence of the modulation frequency f of the incident light for all absorption signals, except for the hydroxyl absorption bands of water and the alcohols. The deviation of the expected frequency dependence points to a modification of the liquid structure toward the surface of the liquid-gas boundary.

Quantitative Analysis of Silica in Silica-Kaolin Mixtures by Photoacoustic and Diffuse Reflectance Spectroscopies

1992 ◽  
Vol 46 (11) ◽  
pp. 1719-1723 ◽  
Author(s):  
Raghoottama S. Pandurangi ◽  
Mohindar S. Seehra
Keyword(s):  
Quantitative Analysis ◽  
Photoacoustic Spectroscopy ◽  
Signal Intensity ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Ir Bands ◽  
Signal Saturation

The techniques of photoacoustic spectroscopy (PAS) and diffuse reflectance spectroscopy (DRS) are investigated for the quantification of silica using the IR bands at 1080,797,693, and 1875 cm−1. It is observed that, in both techniques, signal intensity increases linearly with mass initially. However, signal saturation sets in at much lower masses (>2 mg) in PAS than in DRS (>30 mg), showing that saturation is strongly technique dependent, in addition to having dependence on the absorptivity of the sample. These findings are applied to the quantification of silica in laboratory-generated silica-kaolin mixtures. It is shown that, with the use of the weaker band at 1875 cm−1 in DRS, satisfactory results for the quantification of silica are obtained.

Advantages of Phase Analysis in Fourier Transform Infrared Photoacoustic Spectroscopy

1988 ◽  
Vol 42 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Lionel Bertrand
Keyword(s):  
Fourier Transform ◽  
Phase Analysis ◽  
Thermal Diffusion ◽  
Photoacoustic Spectroscopy ◽  
Diffusion Length ◽  
Fourier Transform Infrared ◽  
Photoacoustic Signal ◽  
Thermal Diffusion Length ◽  
Phase Saturation ◽  
Infrared Photoacoustic Spectroscopy

Fourier transform infrared photoacoustic spectroscopy is greatly improved by the simultaneous measurement of the photoacoustic signal amplitude and phase. Saturation effects, sample dilation, and optical scattering, even in heterogeneous samples, can be easily corrected to give the absorption coefficient real value. Quantitative analyses without any special sample preparation or special photoacoustic cell are now possible. Moreover, the phase of the photoacoustic signal permits depth localization of the absorbing species within the thermal diffusion length. Surface analyses are thus possible that have a depth resolution at least one order of magnitude higher than that obtained by changing the thermal diffusion length. In this paper we illustrate the advantages of phase analysis in Fourier transform infrared photoacoustic spectroscopy with the detection of sorbed water in polyethylene.

Rotational analysis of the 13 200 and 13 400 cm−1 bands of NO2 by means of Fourier transform spectroscopy

1982 ◽  
Vol 60 (9) ◽  
pp. 1288-1302 ◽  
Author(s):  
A. Perrin ◽  
J. -M. Flaud ◽  
C. Camy-Peyret ◽  
P. Luc
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Ground State ◽  
Electronic Transition ◽  
Spin Orbit ◽  
Rotational Analysis ◽  
Coriolis Coupling ◽  
Absorption Bands ◽  
Vibrational Assignments ◽  
Fourier Transform Spectra

The analysis of two parallel absorption bands of NO2, at 13 400 and 13 200 cm−1 respectively, has been performed using high resolution Fourier transform spectra. This paper is an extension of the work performed on the 7390 Å band (13 500 cm−1) in 1977 by Hallin and Merer, and completed in 1980 by Perrin, Camy-Peyret, Flaud, and Luc.The lines involving the Ka = 0, 1, 2, 3, 4 stacks for the 13 400 cm−1 band and Ka = 0, 1, 3, 4 for the 13 200 cm−1 band have been assigned and considerable spin–orbit and/or Coriolis coupling induced transitions have been detected.The 13 400 cm−1 band can be considered as belonging to the [Formula: see text] electronic transition, while the 13 200 cm−1 band might be, as the 7390 Å band (at 13 500 cm−1), a transition within the ground state manifold which barrows its intensity through vibronic coupling from the 13 400 cm−1 band. Tentative vibrational assignments are given.

Quantitative Analysis of a Binary Mixture by Fourier Transform Infrared Photoacoustic Spectroscopy

1981 ◽  
Vol 35 (2) ◽  
pp. 185-186 ◽  
Author(s):  
Mark G. Rockley ◽  
Dennis M. Davis ◽  
Hugh H. Richardson
Keyword(s):  
Fourier Transform ◽  
Quantitative Analysis ◽  
Binary Mixture ◽  
Photoacoustic Spectroscopy ◽  
Fourier Transform Infrared ◽  
Isotopic Shift ◽  
Infrared Photoacoustic Spectroscopy

The isotopic shift of the v2 NO3−1 absorption of mixtures of K15NO3 and K14NO3 at 800 and 825 cm−1 has been used to demonstrate that Fourier transform infrared photoacoustic spectroscopy is a technique which is useful for quantitative analysis of solid mixtures.

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