112
M. A. Czarnecki and S. Morita
[4]. This new approach allows to accept any kind of perturbations and permits the
hetero-correlations between the data obtained from different methods, such as MIRNIR, MIR-Raman, UV-MIR and so on. In this way, the generalized 2D correlation
analysis has begun a powerful and versatile tool for analysis of spectral data from
various experiments [5]. This approach appears to be particularly useful in nearinfrared (NIR) region since NIR spectra are very complex due to overlap of numerous
overtones and combination bands [6, 7]. In addition, 2DCOS spectroscopy solves
the problem of multicollinearity by independent correlation of variables.
The idea behind 2DCOS is very simple and is displayed in Fig. 6.1. The sample is
subjected to external perturbation, which generates the specific changes at a molecular level. These changes can be monitored by any kind of electromagnetic radiation, including NIR. As a result, the measurements provide a series of perturbationdependent spectra. From the single spectra y(ν, t), a perturbation-ordered data matrix
is assembled:
Fig. 6.1 General scheme of
2D correlation spectroscopy
Sample
Elec tromagnetic radiation
(IR, NIR, Raman, UV,...)
Perturbation
-mechanical
-electrical
-chemical
-optica l
-magnetic
-thermal
-...
Dynamic spectrum
y( ,t)
2D correlation analysis
2D correlation spectrum
( 1 , 2 ) — synchronous
( 1 , 2 ) — asynchronous
~
M. A. Czarnecki and S. Morita
[4]. This new approach allows to accept any kind of perturbations and permits the
hetero-correlations between the data obtained from different methods, such as MIRNIR, MIR-Raman, UV-MIR and so on. In this way, the generalized 2D correlation
analysis has begun a powerful and versatile tool for analysis of spectral data from
various experiments [5]. This approach appears to be particularly useful in nearinfrared (NIR) region since NIR spectra are very complex due to overlap of numerous
overtones and combination bands [6, 7]. In addition, 2DCOS spectroscopy solves
the problem of multicollinearity by independent correlation of variables.
The idea behind 2DCOS is very simple and is displayed in Fig. 6.1. The sample is
subjected to external perturbation, which generates the specific changes at a molecular level. These changes can be monitored by any kind of electromagnetic radiation, including NIR. As a result, the measurements provide a series of perturbationdependent spectra. From the single spectra y(ν, t), a perturbation-ordered data matrix
is assembled:
Fig. 6.1 General scheme of
2D correlation spectroscopy
Sample
Elec tromagnetic radiation
(IR, NIR, Raman, UV,...)
Perturbation
-mechanical
-electrical
-chemical
-optica l
-magnetic
-thermal
-...
Dynamic spectrum
y( ,t)
2D correlation analysis
2D correlation spectrum
( 1 , 2 ) — synchronous
( 1 , 2 ) — asynchronous
~