A.2 CBF Transitions

A.2.1 Hydrogen, n = 1,..., 10

following Mihalas

------ C = pa 2 V~ -8k--n V~ T-e-hnth/kTG (T) ik 0 pme e i

own fit formulae for

, because Mihalas is restricted in temperature,
no input parameter

A.2.2 He II, n = 1,..., 10

following Mihalas, like CBF1, own fit formulae for

, because Mihalas is restricted in temperature,
no input parameter

A.2.3 He I, n < 15

------ 8k V ~ -- { 0.728u 2 ( 2.0 + u )} Cik = pa02V ~ -----ne T s0 u0E1(u0) - -------0--E1(u1) - 0.189u02e -u0 --------2- pme u1 u23

u0 = hnth/kT , u1 = u0 + 0.27, u2 = u0 + 1.43

1 input parameter:

₀ (in tabular form by Mihalas & Stone)

A.2.4 Seaton Formula

C = 1.55 .1013gs n V~ 1-e- u0u - 1 g = [0.1,0.2, 0.3] for Z = [1,2, > 3] ik 0 e T 0

Z = charge of the ion

₀ = threshold photoionization cross-section
2 input parameters:

₀,

In case that formula 4 is requested and a cross-section of 0.0 inserted, a mean cross-section (at the threshold energy) of the Opacity Project data is calculated and used as threshold cross-section (Sect. A.4).

A.2.5 Lotz Formula

------ ( ) { } 2 V~ 8k V~ -- EH 2 au0 Cik = pa0 -----ne TP ---- u0 E1(u0) - ----E1(u1) pme E0 u1

3 input parameters: P,

, c
u₁ = u₀ + c

A.2.6 Mg II 3s Mg III 2p⁶ +

following Mihalas (1972)

------ V ~ --( )2 { } Cik = pa02V ~ -8k--ne T EH-- au0E1(u0) + b(u0/u1)2[E1(u1) + e-u1] pme E0

u1 = u0 + c

3 input parameters: a, b, c

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