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# Simplified Multi-State Steric Mass Action¶

The simplified multi-state steric mass action is the same as the multi-state SMA model described above (see Section Multi-State Steric Mass Action), but with additional assumptions:

Molecules are only exchanged between two adjacent states, that is, no transfer from state \(q_{i,1}\) to state \(q_{i,3}\) is allowed.

Characteristic charge \(\nu_{i,j}\) and shielding factor \(\sigma_{i,j}\) only depend on the index of the state \(j\).

Thus, the exchange parameters \(k^{(i)}_{j\ell}\), the characteristic charge \(\nu_{i,j}\), and the shielding \(\sigma_{i,j}\) can be parameterized with few degrees of freedom. For all \(i = 1,\dots,N_{\text{comp}} - 1\) and \(j,\ell = 0,\dots,M_i - 1\) let

Note that the characteristic charge \(\nu_{i,j}\) has to be monotonically non-decreasing in the second index \(j\) and all other rates and the steric factor \(\sigma_{i,j}\) have to be non-negative.

For more information on model parameters required to define in CADET file format, see Simplified Multi-State Steric Mass Action.