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Online-Manual

• Main Window
• File
• Spectra
• Calculations
Addition
Subtraction
Multiplication
Division
Spectra Averaging
Y Constants
X Constants
Derivative
Transmission/Reflection
Degree of Polarisation
Raman Shift
Concentration
Effective Absorbance
Center of Gravity
Film Thickness
Quantum Yield
Low Temp. Quantum Yield

• Fluorescence/EEM
• Gaussfit
• Plot/Options
• Help

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Just released! The brand-new, top-modern successor software for Spekwin32 Spectragryph 1.0

Calculations menu

1. Menu Item [Addition]

• The y values of the two spectra selected in the drop down list will be added. [all spectra] will execute the operation on all spectra present, taking the spectrum selected in the lower dropdown list for calculation.
  
  
• The new spectrum will be added to the spectra list, its legend titel will be "Addition". [Keep legend text] will retain the original legend text for the resulting spectrum.
  
  
• The new spectrum's start and end wavelength will be determined by the overlapping range of the two selected spectra, the x axis stepwidth is taken from the upper spectrum.
  
  

2. Menu Item [Subtraction]

• The y values of the spectrum selected in the lower drop down list will be subtraced from the y values of the spectrum selected in the upper drop down list. [all spectra] will execute the operation on all spectra present, taking the spectrum selected in the lower dropdown list for calculation.
  
  
• The new spectrum will be added to the spectra list, its legend titel will be "Subtraction". [Keep legend text] will retain the original legend text for the resulting spectrum.
  
  
• The new spectrum's start and end wavelength will be determined by the overlapping range of the two selected spectra, the x axis stepwidth is taken from the upper spectrum.
  
  

3. Menu Item [Multiplication]

• The y values of the two spectra selected in the drop down list will be multiplicated by each other.[all spectra] will execute the operation on all spectra present, taking the spectrum selected in the lower dropdown list for calculation.
  
  
• The new spectrum will be added to the spectra list, its legend titel will be "Multiplication". [Keep legend text] will retain the original legend text for the resulting spectrum.
  
  
• The new spectrum's start and end wavelength will be determined by the overlapping range of the two selected spectra, the x axis stepwidth is taken from the upper spectrum.
  
  

4. Menu Item [Division]

• The y values of the spectrum selected in the upper drop down list will be divided by the y values of the spectrum selected in the lower drop down list.[all spectra] will execute the operation on all spectra present, taking the spectrum selected in the lower dropdown list for calculation.
  
  
• The new spectrum will be added to the spectra list, its legend titel will be "Division". [Keep legend text] will retain the original legend text for the resulting spectrum.
  
  
• The new spectrum's start and end wavelength will be determined by the overlapping range of the two selected spectra, the x axis stepwidth is taken from the upper spectrum.
  
  

5. Menu Item [Spectra Averaging]

• The y values of the selected spectra (left mouse button) will be averaged.
  
  
• The new spectrum will be added to the spectra list, the legend title can be set in the lower edit field.
  
  

6. Menu Item [Y Constants]

• Apply one of four calculation types to the spectrum selected in the upper drop down list. The new spectrum will be added to the spectra list.
  
  
• Options:
  • with "all spectra of one type", you can treat all spectra of a certain type simultaneously.
  • [remove original(s)] removes the original spectrum/spectra.
  • [append "+ | – | × | ÷ | n |"] appends calculation type and figure to the legend titel of the new spectrum/spectra.
    
    
• Hint: For multiplication with resp. enter x2 resp. x4 into the edit field. This feature is helpful when you have to display fluorescence spectra in wavenumbers. Generally you can multiplicate with by entering xn (n: real number). The other calculation types are also applicable.
  
  

7. Menu Item [X Constants]

• Depending on the selected calculation type, you can move spectra to left/right, stretch and compress along the x axis.
  
  
• Works only if the spectrum's x axis type is identical with the currently displayed x axis type in the graph window.
  
  
• The new spectrum will be added to the spectra list, its legend title appended by the calculation type and the figure from the edit field.
  
  
• Hint: Please use this function only if you really know what you are doing, since it modifies the spectra in a rather unusual manner.
  
  

8. Menu Item [Derivative]

• First, second, third or fourth derivative of the spectrum selected in the drop down list will be calculated.
  
  
• The new spectrum will be added to the spectra list, its legend title appended by "x. Derivative".
  
  Options:
  • with "derive all spectra", you can treat all spectra simultaneously.
  • [remove original(s)] removes the original spectrum/spectra.
  • [smooth before derivation] uses a smoothed spectrum for the derivative function. This feature virtually eliminates the influence of measurement noise.
    
    
• Even higher order derivatives can be obtained by repeated derivation of derived spectra. The smoothing option is strongly recommended for all derivatives higher than the first derivative.
  
  

9. Menu Item [Transmittance/Reflectance]

• From two intensity spectra (sample and background/reference), the transmittance or reflectance will be calculated after T = I/I_0.
  
  

10. Menu Item [Degree of Polarisation]

• When processing polarization dependent fluorescence and excitation spectra, it is often necessary to calculate the degree of polarisation and a reduced spectrum.
  
  
• This can be done from two spectra with different polarizer orientations according to the following equations:
  and
  

  with	:	reduced spectrum
  	:	degree of polarisation
  	:	fluorescence intensity with crossed polarizers
  	:	fluorescence intensity with parallel polarizers

  
  
• The two spectra are selected in the two drop down lists. The new spectrum will be added to the spectra list, the legend title of the new spectrum consists of the legend title of the spectrum and the new spectral type.
  
  
• To calculate all spectra at once, use the option [all]. This works only for spectra of *.ggg type.
  
  

11. Menu Item [Raman Shift]

• Calculate a Raman shift spectrum from a (fluorescence) intensity spectrum in the wavelength scale and by providing the laser excitation wavelength.
  
  
• As the area around 0 cm-1 is usually distorted due to the laser emission itself, you can define the start wavenumber of the Raman spectrum.
  
  
• Two more options are available:
  • [transform all spectra] applies the transformation to all loaded spectra at once.
  • [remove original(s)] removes the original wavelength spectrum/ spectra from display.
    
    

12. Menu Item [Concentration]

• In addition to the menu item [General], this is the second possibility to set the concentration for a certain spectrum. For this function, the molar absorption coefficient has to be known. The calculation is done via Lambert-Beer.
  
  
• All entered values apply only to the spectrum selected in the upper drop down list. Upon entry of molar absorption coefficient, wavelength and absorption path length, you can calculate the concentration with the button [Calculate].
  
  
• You can enter the maximum of the current spectrum automatically with the button [Insert Peak].
  
  
• Hint: For directly entering the concentration, use the menu item [General].

13. Menu Item [Effective Absorbance]

• For the determination of fluorescence quantum yields it is important to know the fraction of light absorbed by the sample. Due to the finite bandwith of the excitation light, this has to be averaged across the bandwidth range, yielding the "effective absorbance".
  
• The following formula is used:

  with	:	absorption spectrum
  	:	bandwidth of excitation light

  
  
• Normally, the bandpass is a XXX function characterised by its center wavelength and bandwidth.
  
  

14. Menu Item [Center of Gravity]

• For the spectrum selected in the drop down list, the center of gravity will be calculated. I. e. the mean of x values resp. weighted by the y values (absorbances resp. ) after the following equation:
  respective:
  
  
• The current x axis range will be used as integration boundaries. The result will be shown in the middle part of the status bar.
  
  
• Hint: the center of gravity in wavelength scale does not correspond to the reciprocal center of gravity in wavenumbers scale : !
  
  

15. Menu Item [Film Thickness]

• From a white-light reflectance spectrum spectrum showing interference, the thickness of a single-layer thin film can be calculated. As input values, the refractive index of the film material is needed together with the incident angle of the reflected light (perpendicular illumination means an angle of 0°) The wavelength range used can be changed.
  
  
• The results window contains the input data, the number of evaluated peaks and the calculated thickness together with a qualita measure (StDev). A StDev value higher than a few percent of the thickness value indicates an invalid result.
  
  
• This is a new and experimental feature, user feedback is strongly needed and important for the future development of this feature! Do not use this method without cross-checking the results by an alternative method!
  
  

16. Menu Item [Quantum Yield]
This menu item is too complicated to explain here. Ask me directly for explanations.

17. Menu Item [Low Temp. Quantum Yield]
A useful explanation would go beyond the scope of this manual.