implement simpler splitting method

[kaschau]

See

Efficient time-stepping techniques for simulating turbulent reactive flows with stiff chemistry,
Computer Physics Communications, Volume 243, 2019, Pages 81-96,
https://doi.org/10.1016/j.cpc.2019.04.016.

[kaschau]

https://epubs.siam.org/doi/pdf/10.1137/120878641?casa_token=FnAP7D-OjvMAAAAA:NDofHR4t61QLQPzYRlaUBPCafJYEVl0mNw9LHaDh4R_l7KQpaZ9fJIaxCblRZP685mUcZwU