Chapter 2
Polarization Modulation Infrared
Reflection Absorption Spectroscopy: From
Theory to Experiment
PM IRRAS is an advanced structure analyzing technique. The propagation of the
electromagnetic radiation in a medium and its reflection and refraction describe the
reflectivity of the incoming beam from a phase boundary and transmissivity into a
second medium, respectively. When the wavelength of the incoming electromagnetic radiation corresponds to the spectral region of the IR light and this radiation
encounters a metal surface, the IR beam is almost fully reflected from its surface. The
reflectivity of the IR light depends in the state of polarization of the incoming
radiation [1]. This property gives the theoretical background of IRRAS. When the
incoming IR radiation is double modulated: at the Fourier transform IR spectrometer
and at a photoelastic modulator, the measured signal provides a differential spectrum
which is proportional to the absorbance of the species absorbing the IR light on the
mirror surface [2]. In this chapter the theory of the propagation of the electromagnetic
radiation in a condensed medium and theoretical backgrounds of IRRAS are
described. The fundamentals of PM IRRAS and in situ electrochemical PM
IRRAS have been previously described by Zamlynny and Lipkowski [3]. For
completion of this presentation, the theory of IRRAS and PM IRRAS is described
below based on existing literature [3, 4].
2.1 Propagation of Infrared Radiation in a Medium and Its
Reflection and Transmission at Interfaces
The propagation of an electromagnetic wave (e.g. IR radiation) in a medium is
characterized by orthogonal vectors: electric field (E) and magnetic induction field
(B) which are normal to the direction of the wave vector (K direction of the wave
propagation). The propagation of the electromagnetic wave in vacuum is described
by the wave equation which describes E at any moment of time (t) and at any
distance (x) from the arbitrary set origin
© Springer Nature Switzerland AG 2020
I. Brand, Application of Polarization Modulation Infrared Reflection Absorption
Spectroscopy in Electrochemistry, Monographs in Electrochemistry,
https://doi.org/10.1007/978-3-030-42164-9_2
7
Polarization Modulation Infrared
Reflection Absorption Spectroscopy: From
Theory to Experiment
PM IRRAS is an advanced structure analyzing technique. The propagation of the
electromagnetic radiation in a medium and its reflection and refraction describe the
reflectivity of the incoming beam from a phase boundary and transmissivity into a
second medium, respectively. When the wavelength of the incoming electromagnetic radiation corresponds to the spectral region of the IR light and this radiation
encounters a metal surface, the IR beam is almost fully reflected from its surface. The
reflectivity of the IR light depends in the state of polarization of the incoming
radiation [1]. This property gives the theoretical background of IRRAS. When the
incoming IR radiation is double modulated: at the Fourier transform IR spectrometer
and at a photoelastic modulator, the measured signal provides a differential spectrum
which is proportional to the absorbance of the species absorbing the IR light on the
mirror surface [2]. In this chapter the theory of the propagation of the electromagnetic
radiation in a condensed medium and theoretical backgrounds of IRRAS are
described. The fundamentals of PM IRRAS and in situ electrochemical PM
IRRAS have been previously described by Zamlynny and Lipkowski [3]. For
completion of this presentation, the theory of IRRAS and PM IRRAS is described
below based on existing literature [3, 4].
2.1 Propagation of Infrared Radiation in a Medium and Its
Reflection and Transmission at Interfaces
The propagation of an electromagnetic wave (e.g. IR radiation) in a medium is
characterized by orthogonal vectors: electric field (E) and magnetic induction field
(B) which are normal to the direction of the wave vector (K direction of the wave
propagation). The propagation of the electromagnetic wave in vacuum is described
by the wave equation which describes E at any moment of time (t) and at any
distance (x) from the arbitrary set origin
© Springer Nature Switzerland AG 2020
I. Brand, Application of Polarization Modulation Infrared Reflection Absorption
Spectroscopy in Electrochemistry, Monographs in Electrochemistry,
https://doi.org/10.1007/978-3-030-42164-9_2
7