Input

This is the typical snapshot of the input of ComplexRI. Each part will be explained in the following.

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①Title

Please input the title of your job (alphabet). The output results of ComplexRI will be saved in the excel format with the name @Title.xlsx

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②File

Please upload the ATR-IR experimental data in this part. The inside should be like the following.

There are two rules for the format of input file.

(1). The format of input file must be txt.

(2). The columns are separated by the space.

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③The order of data

Please select the sort order of your data.

Ascending order: The frequencies in the input file are in ascending order (left picture). (Default)

Descending order: The frequencies in the input file are in descending order (right picture).

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④Reflectance or Absorptance?

Please select the type of your ATR-IR data.

Reflectance(%): The Reflectance of ATR-IR spectra in the value of percentage. (Default)

Reflectance: The Reflectance of ATR-IR spectra.

Absorptance: The Absorptance of ATR-IR spectra.

The relationships between each data are

$Reflectance(\%)=Reflectance*100$

$Absorptance=-\log _{10}(Reflectance)$

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⑤Select the column of your data

Please input the column number of the data you want to analyze in your ATR-IR file.

Wavenumber: The column number of wavenumber in your input file. (Default: 1)

ATR-IR data: The column number of ATR-IR data in your input file. (Default: 2)

For example, an input file like following can be uploaded and column 1 and column 5 can be selected for analyzing.

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⑥Input the fitting range

Please input the frequency range (in wavenumber) you want to perform the fitting. ComplexRI will fit the data only inside the range you input here.

minimum wavenumber: The lower boundary of wavenumber. (Default: 1636)

maximum wavenumber: The upper boundary of wavenumber. (Default: 1863)

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⑦Select the Substrate

Please select the substrate you used in the ATR-IR experiment. Here, we prepare the three substrates often used

Diamond(Refractive Index = 2.38)

Zinc selenide(Refractive Index = 2.40)

Germanium(Refractive Index = 4.0).

You can also input the refractive index of your substrate by selecting Others in the list.

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⑧Incident angle in ATR-IR

Please input the incident angle in your ATR-IR experiment. (Default=45 degree)

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⑨Refractive index of target sample in non-resnance region

Please input the refractive index of the target sample non-resnance region. (Default=1.360)

The refractive index of target sample in non-resnance region should be determined before the fitting procedure. In the reference paper, we use the refractive index values in the visible regions to fit Cauchy's equation.

$n=A+{\frac {B}{{\lambda }^{2}}}+{\frac {C}{{\lambda }^{4}}}$

The obtained parameters $A,B,C$ were used to evaluate the refractive index at 5000 wavenumber.

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⑩The tolerance of fitting ?

Please input the tolerance of fitting procedure. The fitting will be finished when the calculated residual is less than this value.

The details are written in the explanation01 of Internal processing.

Notice!! Fitting can not finish if this value is too small.

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11：How to set the parameter of the fitting function

Here, you can select whether you decide the parameter of fitting functions. We use a set of Lorentz functions for fitting of Reflectance spectra as mentioned in the

explanation01 of Internal processing . Fitting function is like below.

$n_{j}=n_{j}^{0}+\sum _{l=1}^{lmax}{\frac {A}{\nu _{l}-\nu -i\gamma }}$

The default is set to “NO” like below.

In this pattern, the parameters are assigned automatically.

If you select “YES” like below.

The new input fields are set, and you should give the number of Lorentz functions like below. The maximum of the number is 7.

Above, the number is set to 1. So, the one set of three parameters of Lorentz function is need to input. init_A1, init_N1 and init_G1 are the amplitude, peak wavenumber, and bandwidth of Lorentz function, respectively.