Isotopic and vibrational-level dependence of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> dissociation by electron impact

The low-energy electron-impact dissociation of molecular hydrogen has been a source disagreement between various calculations and measurements for decades. Excitation the ground state ${\mathrm{H}}_{2}$ into dissociative $b{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{\ensuremath{\Sigma}}}_{u}^{+}$ is now well understood, with most recent being in excellent agreement convergent close-coupling (MCCC) both integral differential cross sections [Zawadzki et al., Phys. Rev. A 98, 062704 (2018)]. However, absence similar vibrationally excited or isotopically substituted ${\mathrm{H}}_{2}$, these species must be determined by theory alone. We have identified large discrepancies MCCC recommended $R$-matrix ${\mathrm{D}}_{2}$, ${\mathrm{T}}_{2}$, HD, HT, DT [Trevisan Plasma Contr. Fusion 44 1263 (2002); 44, 2217 (2002)], isotope effect dependence on initial vibrational level. Here we investigate discrepancies, discuss consequences plasma models, which incorporated previously data.