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2.3 Description of the Keywords

The expression “card” which is frequently used in the following is a relic from the PUNCH era and is used for historical reasons.

keyword .

comment, not written to atomic data file

keyword 0 (Null)

necessary to end the validity of some keywords (e.g. L, LTE, ...)

keyword ATOM

introduces a new element. The following card indicates:

  1. the chemical abbreviation (FORMAT A2),
  2. charge of the lowest ionization stage (in e-) in model atom,
  3. atomic weight (in AMU).

Example:

ATOM
HE 0 4.0026

means: all following cards describe an helium model atom, starting with neutral helium He I, the atomic weight is 4.0026 AMU.

keyword L

introduces non-LTE levels. All cards following this keyword indicate:

  1. level name (FORMAT A10, Sect. 2.1),
  2. name of ground state of the following ionization stage (FORMAT A10, Sect. 2.1), if no parent exists: NONE,
  3. energy to the ionization limit in Hz,
  4. statistical weight, if no parent exists: 1.0.

Example:

L
HE26 |~| |~| |~| |~| |~| |~| HE31 |~| |~| |~| |~| |~| |~| 3.6548882425E+14   72
0

levels of an ionization stage are expected in increasing energetic order (from the ground state). The keyword 0 completes the list of NLTE levels for this ionization stage.

keyword LTE

introduces LTE levels analogously to the keyword L. Do not forget to complete the list with the keyword 0. Important: some formulae for the free-free opacity (Sect. A) expect at least one LTE level in the respective ion. Attention: this is not checked by the program.

Radiative and collisional transitions are introduced by:

RBB
radiative bb
RBF
radiative bf
RDI
radiative dielectronic bf
RLL
radiative bb for “sample” cross-section within one level band (complex ions)
RLU
radiative bb for “sample” cross-section
CBB
collisional bb
CBF
collisional bf
CBX
collisional from NLTE to LTE levels

All lists following these keywords have to be completed by the keyword 0. A card which follows one of the keywords (except RDI) indicates

  1. lower level (A10),
  2. upper level (A10),
  3. formula number for the calculation of the cross-section (Sect. A),
  4. number n of following input data,
  5. n input data for the calculation of the cross-section.

Example:

RBB
H11 |~| |~| |~| |~| |~| |~| |~| H13 |~| |~| |~| |~| |~| |~| |~| 1   1  0.0791
0

This is the line transition Lyb, cross-section calculation with formula No. 1, one input number (0.0791).

For RDI transitions a third level is introduced between lower and upper level which is the upper level of the stabilizing transition and has to be introduced before as a LTE level.

For RLU and RLL transitions the level names are followed by the name of the file which contains the “sample” cross-section.

Example:

RLU
FE31 |~| |~| |~| |~| |~| |~| FE33 |~| |~| |~| |~| |~| |~| 26_02_01_03
0

keyword RFF

introduces radiative free-free transitions. The following card indicates:

  1. the ionization stage (A10, chemical element abbreviation + ionization stage, e.g. HE2),
  2. formula number for the calculation of the cross-section (Attention: Def. LTE!)
  3. number n of the following input data,
  4. n input data.

keyword TL

The card which follows this keyword indicates the “line temperature” Tline for all following RBB transitions. This is necessary to change the temperature used for the calculation of the Doppler width (default Tline = 3 4Teff) in the creation of the frequency grid (Sect. 3). The default is again valid after

TL
0

keyword DB

introduces an explicit frequency grid for all following RBB transitions. The following card indicate:

  1. number n of frequency points of the line,
  2. n frequency points (distance from line center in Doppler widths!).

Example:

DB
7
-3 -2 -1 0 1 2 3

If the first frequency point is 0.0, only “half” lines are created.

This grid is valid until the next keyword DB appears. The default is valid after

DB
0

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