software to fit optical spectra - Quantum Materials Group

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Figure 3-16 The best model and data match for the model with one Lorentz terms and one Drude term. Figure 3-17 The model with one Lorentz terms and one Drude term, giving the best match to the data. Having obtained such a fit, you might want to see the corresponding dielectric function. Let us open a new graph window (by choosing ‘Graph’ from the ‘Window’ menu). Open the “Graph properties” window by double-clicking on the gray area. Change the Y-axis range to [- 20;+20] and Y-axis title to “E1,E2” (Figure 3-18). Guide to RefFIT Page 34
Figure 3-18 The “Graph properties” window. Then open the “Graph contents” window by double-clicking on the white area (Figure 3-3) and move items “MODEL [E1] “Model1”” and “MODEL [E2] “Model1”” to the list “Graph curves”. Now we can see the real and imaginary parts of the dielectric function (ε1 and ε2) on the same graph (Figure 3-19). Of course, in this way you can plot also other curves, like conductivity, penetration depth, loss function etc. Figure 3-19 The real and imaginary part of the dielectric function, plotted on the same graph. In order to have some outcome you may want export some curves, calculated by a model. To do this you should activate a graph window and press the SPACEBAR. You can then specify the file name in the “Export Graph to ASCII” window. All the model curves on the graph will be stored as separate columns in this file. At this moment it is not yet possible to specify, which set of frequencies will be used to generate the model curves. The computer will take the frequency range exactly the same as on the horizontal scale of the graph. The resolution will correspond to the resolution of your screen. Please, do not complain. It used to be a temporary solution, but I did not make a better one. However, you can export data with an adjustable set of frequencies using a macro (see section 4.11.6). Guide to RefFIT Page 35
Page 1 and 2: Last updated: 20.04.2004 Guide to R
Page 3 and 4: 4.8. Dataset manager ..............
Page 5 and 6: that time. The later development of
Page 7 and 8: 1.4. Let’s keep in touch Please,
Page 9 and 10: 2.1.1. Levenberg-Marquardt algorith
Page 11 and 12: Guess initial parameters p , , p 1
Page 13 and 14: achieve a proper ‘balance’ betw
Page 15 and 16: The third requirement is that at ve
Page 17 and 18: Equation 2-19 is useful to estimate
Page 19 and 20: The first problem is that the Loren
Page 21 and 22: The problem can be circumvented by
Page 23 and 24: In these cases the fitting of the d
Page 25 and 26: 3. Tutorial This chapter shows how
Page 27 and 28: Figure 3-3 Graph contents window is
Page 29 and 30: Figure 3-7 Click the button and in
Page 31 and 32: If you are still far from this fitt
Page 33: Figure 3-15 The model and experimen
Page 37 and 38: Figure 3-20 Loading the reflectivit
Page 39 and 40: Figure 3-22 The general RefFIT view
Page 41 and 42: Figure 3-25 The general RefFIT view
Page 43 and 44: MainWindow(XPos = 0, YPos = 0, Widt
Page 45 and 46: emarkable ‘anomaly’, related to
Page 47 and 48: ###################################
Page 49 and 50: # restores the original application
Page 51 and 52: 4. Reference 4.1. System requiremen
Page 53 and 54: Figure 4-2 The “Parameter control
Page 55 and 56: The model file stores information a
Page 57 and 58: considering multiple (Fabri- Perot)
Page 59 and 60: optical conductivity in practical u
Page 61 and 62: Kronig friendly, so be careful! “
Page 63 and 64: function. This command cannot be us
Page 65 and 66: Iinc Itrans ε ε ( 1) ( 2) … (n)
Page 67 and 68: In ellipsometry the complex ratio
Page 69 and 70: ` Figure 4-10 The experimental conf
Page 71 and 72: Here ω p and ∞ ε are considered
Page 73 and 74: points “#pts” and the grid type
Page 75 and 76: 4.9.2. Graph contents To set the gr
Page 77 and 78: Available ChiSq terms and click the
Page 79 and 80: At each iteration a linear equation
Page 81 and 82: Before a macro is actually executed
Page 83 and 84: Quantity Text Abbreviation of the q
Page 85 and 86:
Parameters: Name Type Description W
Page 87 and 88:
“Wp” - plasma frequency; “G
Page 89 and 90:
ShowLine Integer =12: Chalk =13: Br
Page 91 and 92:
XMin Double Minimal X (frequency) v
Page 93 and 94:
always come in pairs. All commands
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