The File Format

The File Format

Cross-section data must be specified using the following format:

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energy data (eV) Collision cross section (m2)

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1

1st line: Keyword in capitals indicating the type of the collision. Possible collision types are ELASTIC, EXCITATION, IONIZATION, and ATTACHMENT. Note the use of capital letters.

2

2nd line: Reaction formula. This formula carries over to the COMSOL Multiphysics GUI so that whatever is entered here appears in the field. The formula must be separated by a => sign.

3

3rd line: For elastic collisions, the ratio of the electron mass to the target particle mass. For attachment, the 3rd line is 0 (zero). For ionization, the threshold energy in eV. For excitation there are three (3) numbers separated by a space. The first number is the excitation energy (eV). The second number is the ratio of statistical weights of the final state to the initial state. The third number is a flag that determines whether or not a detailed balance is used. Use a 1 to construct a detailed balance and 0 otherwise.

4

4th line: Two unit conversion factors by which the columns of data are multiplied.

5

Table of the cross section as a function of energy. The table starts and ends by a line of dashes '------' (at least five), and has otherwise two numbers per line: the energy in eV and the cross section in m2. The table does not need to follow the other lines immediately; that is, user comments such as reference information can be included above the table.

Here are some examples for the types of collisions available:

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0.000000e+000 3.500000e-021

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5.800000e-002 2.220446e-036

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1.627000e+000 2.220446e-036

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1.206000e+001 2.220446e-036

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