A system of mass balance equations is set up for plasma-chemical simulations, we derive the diffusion velocities from Stefan-Maxwell theory. An algorithm to linearly transform the system of mass balance equations in the context of non-LTE plasmas is described. This transformation is derived from the reaction set, and eliminates part of the chemical source term, enforces invariants such as conservation of mass and quasi-neutrality up to machine precision, provides a reduction in the number of unknowns, and significantly improves conditioning of the discretized system. The MATLAB code used in the numerical experiments is available on GitLab: https://gitlab.com/ChrisSchoutrop/stoichiometric-transformation.

建立了用于等离子体化学模拟的质量平衡方程组，我们从Stefan-Maxwell理论推导了扩散速度。描述了一种在非LTE等离子体环境中线性转换质量平衡方程组的算法。这种变换是从反应集中得出的，消除了部分化学来源项，强制执行不变性，例如质量守恒和准中立性直至机器精度，减少了未知数，并显着改善了离散化条件系统。可在GitLab上获得用于数值实验的MATLAB代码：https：//gitlab.com/ChrisSchoutrop/stoichiometric-transformation。