Benchmarking quantum chemistry compound methods for the temperature‐dependent thermochemical data of Si_xH_y and Si_xF_y series

Abstract

Accurate thermochemical data of SixHy and SixFy series is a prerequisite for high‐end materials design. In this study, the standard enthalpies of formation (∆fHnormalθ) of SixHy and SixFy were calculated from atomization and isodesmic reactions using the composite methods CBS‐QB3, G3, G4, W1U, W1BD, and W2‐F12. Second, their temperature‐dependent thermochemical parameters (∆𝑓𝑆θ and Cp) are derived from the optimized geometries and frequency calculation at B3LYP/cc‐pV(T + d)Z level. In addition, this paper uses nonexpert‐user methods (CBS‐QB3, G3, G4, W1U and W1BD) to compare the calculated ∆fHnormalθ with recommended values of Active Thermochemical Table, Burcat database, and W2‐F12 calculation results. The accuracy of these nonexpert‐user methods are interpreted in terms of descriptive statistics. The results show that: (1) the accuracy rank of individual compound methods is as follows: CBS‐QB3 > W1BD > W1U > G4 > G3; (2) for Si/H/F compounds, three combination methods, CBS‐QB3/G4/W1U or CBS‐QB3/G4/W1BD, and two combination methods, G4/W1U or G4/W1BD, were quite powerful, and the weighted results could reproduce the recommended values within “near‐chemical‐accuracy,” (3) the popular W1BD and W1U methods give highly erroneous results, indicating that one should not apply these methods in isolation unless other error‐cancellation strategies are collocated indicated.

Research Progress on the Mechanism of the Effective Components of Duzhong (Eucommiae Cortex) on Lumbar Disk Herniation

“…Zhang et al 43 found that VEGF mediated pain together with immune T cells and B cells, while Duzhong (Eucommiae Cortex) could effectively regulate inflammatory and immune responses and produce analgesic effects on peripheral nerve roots. Guo et al 44 found that the iridoid components contained in Eucommia bark, flowers, and leaves could exert analgesic effects by regulating sodium ions and glutamate receptors. Si et al 45 studied quercetin and sciatic nerve pain in rats and found that quercetin could inhibit the signal pathway Wnt/β-catenin and downstream COX-2 and iNOS targets, and alleviate sciatic nerve pain.…”

Refining the thermochemical properties of CF, SiF, and their cations by combining photoelectron spectroscopy, quantum chemical calculations, and the Active Thermochemical Tables approach

“…In fact, while in the case of CF and CF + the situation is relatively benign, there being available thermochemical values for CF that arguably appear reliable, things are veritably more complicated in the case of SiF and SiF + . Namely, the values for the enthalpy of formation of SiF available from the literature 24,25,29,69,71,77–88 encompass a spectacularly wide range, differing on the extremes by more than 16 kcal mol −1 , as demonstrated in Table 3. In principle, one might venture assuming that the values reported from the three most accurate electronic structure approaches 71,81,82 are likely the most reliable.…”

“…In fact, while in the case of CF and CF + the situation is relatively benign, there being available thermochemical values for CF that arguably appear reliable, things are veritably more complicated in the case of SiF and SiF + . Namely, the values for the enthalpy of formation of SiF available from the literature 24,25,29,69,71,[77][78][79][80][81][82][83][84][85][86][87][88] encompass a spectacularly wide range, differing on the extremes by more than 16 kcal mol À1 , Fig. 6 Energies of the lowest vibrational levels of the electronic ground state of SiF + with respect to its v + = 0 level as a function of…”

SGLFormer: Spiking Global-Local-Fusion Transformer with high performance

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