Context <p>High-nitrogen polycyclic compounds have become a research hotspot in the design of new energetic molecules due to their dense nitrogen content, high positive enthalpy of formation, and good structural stability. In particular, the fused structures of triazole and triazine heterocycles can not only enhance energy output but also possess excellent thermal stability. This study focuses on three triazolotriazine energetic compounds: 3,7-dinitro-[1,2,4]triazolo[5,1-c][1,2,4]triazin-4-amine (TTX), 7-nitro-3-(1H-tetrazol-5-yl)-[1,2,4]triazolo[5,1-c][1,2,4]triazin-4-amine (compound 1), and 3,3′-dinitro-[7,7′-bi[1,2,4]triazolo[5,1-c][1,2,4]triazine]-4,4′-diamine (compound 2). By employing quantum chemical calculation methods, the study delves into the stability and initial decomposition effects of these compounds under different external electric fields. The research results indicate that external electric fields have a significant impact on the stability and initial decomposition of triazolotriazine energetic compounds, providing an important theoretical basis for the design and application of energetic materials.</p> Method <p>The B3LYP-D3 method combined with the 6-311G(d,p) basis set was used for geometric optimization and frequency analysis on the Gaussian 16 program. All optimized structures were local energy minima on the potential energy surface, with no imaginary frequencies. The M062x method was employed for transition state calculations, and all transition state structures had only one imaginary vibrational mode, which was verified to correctly connect the reactants and products through intrinsic reaction coordinate (IRC) calculations. The Shermo program was used to calculate the Gibbs free energy of the molecules, with all energy results being relative Gibbs free energies with the initial reactants’ energy set to zero. VMD and Multiwfn software was utilized for wavefunction analysis.</p>