software to fit optical spectra - Quantum Materials Group

More documents

Recommendations

Info

“Rs” Grazingincidence reflectivity (spolarization) “Rps” Ratio between Rp and Rs “E1” The real part of the dielectric function “E2” The imaginary part of the dielectric function R s R α R s average , where N ∑ wi average = i= 0 N ∑ i= 1 R (θ ) 1 ⎛ i − N / 2 ⎞ wi = , θ i = θ⎜1 + sd ⎟ , N + 1 ⎝ N ⎠ ( N = 10 ), 2 R ( ) = r ( θ ) r s s θ s cosθ − ( θ ) = cosθ + R ps R ps average , where Guide to RefFIT Page 58 s w N ∑ wi average = i= 0 N i i ε − sin ε − sin R ∑ i= 1 ps w i 2 2 i , θ θ (θ ) 1 ⎛ i − N / 2 ⎞ wi = , θ i = θ⎜1 + sd ⎟ , N + 1 ⎝ N ⎠ ( N = 10 ), 2 R ( ) = r ( θ ) r ps θ ps ps r ( θ ) = r “S1” The real part of the optical conductivity in practical units π σ 1 × 15 “S2” The imaginary part of the π σ 2 × 15 p s 2 2 sin θ − cosθ ε − sin θ = 2 2 sin θ + cosθ ε − sin θ , - angle of incidence (θ ), angle spread ( s θ ), scaling factor of R ( α R ) - angle of incidence (θ ), angle spread ( s θ ) ε - - 1 ε - - 2 Ω -1 cm -1 - Ω -1 cm -1 -
optical conductivity in practical units “N1” The real part of the refraction index “N2” The imaginary part of the refraction index (extinction coefficient) “PD” Penetration depth 1 2πn2ω “LF” Loss function ⎛ 1 ⎞ ε 2 Im⎜− ⎟ = 2 2 ⎝ ε ⎠ ε + ε Table 4-2 The output quantities of the “Dielectric Function” model. 4.6.1. Drude-Lorentz dielectric function n - - 1 n - - 2 1 cm - Guide to RefFIT Page 59 2 - - The physical meaning of the Drude-Lorentz (DL) dielectric function and its parameters is described in section 2.2.3. The dimensionless ε ∞ is stored in the “Einf” field. Each row in the “Lorentzians” table corresponds to one oscillator. The transverse frequency ω 0 is taken from the column “Wo” (measured in cm -1 ), plasma frequency ω p – from column “Wp” (measured in cm -1 ), and linewidth γ (measured in cm -1 ) – from column “G”. The light frequency ω is measured in cm - 1 as well. The Drude term is a particular case of the Lorentz term, with ω 0 = 0 . In this case ω 0 must be fixed (not active in fit). 4.6.2. Special dielectric functions In addition to the standard Drude-Lorentz model RefFIT has a number of extra built-in formulas for the dielectric function. In this section we will describe all of them. The parameters of the extra (special) dielectric functions can be stored in the “Lorentzians” table of the model window, using a ‘trick’, similar to the one intended to distinguish the Dielectric Function model from other (special) models (section 4.5). By default, RefFIT assumes that each row in the “Lorentzians” table corresponds to a Lorentz oscillator. However, if the “Wo” column contains a negative integer value, e.g., -10 (it should be also fixed!), RefFIT considers the parameters in the “Wp” and “G” columns as the ones of a special dielectric function. The particular type of a dielectric function is determined by the number in the “Wo” column. Some special functions depend on more than two parameters, so that two or more rows are necessary to store them.
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 and 34: Figure 3-15 The model and experimen
Page 35 and 36: Figure 3-18 The “Graph properties
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: considering multiple (Fabri- Perot)
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
show all

software to fit optical spectra - Quantum Materials Group

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?