Vacuum synthesis and determination of the ionization energies of different molecular orbitals for BrOBr and HOBr

Pure BrOBr and HOBr were synthesized in vacuum by heterogeneous reactions of the dried bromine vapor and Br2/H2O mixture vapors (5:1) with HgO, respectively, and then characterized by He I photoelectron spectroscopy (PES) and augmented by ab initio GAUSSIAN 2 and the outer valence Green's functional calculations. The first PE band at 10.26 eV with vibrational spacing 550±60 cm–1 and the second PE band at 11.23 eV with vibrational spacing 240±60 cm–1 are, respectively, assigned as ionizations of the electrons of the highest occupied molecular orbital (HOMO)(6b1(39)) and the SHOMO(13b2(38)) orbitals of BrOBr. The first PE band at 10.73 eV with vibrational spacing 750±60 cm–1 and the second PE band at 11.56 eV with vibrational spacing 650±60 cm–1 are, respectively, assigned as ionizations of the electrons of the HOMO(6a[double-prime](22)) and the SHOMO(16a[prime](21)) orbitals of HOBr. The study does not only provide vacuum synthesis conditions for preparing pure BrOBr and HOBr, but also provide experimental PES results along with theoretical ionization energies of different molecular orbitals for BrOBr and HOBr

Maximum Efficiency Per Ampere Control of Synchronous Reluctance Motor Sensorless Drives

The maximum efficiency per ampere (MEPA) control strategy stands out as a highly effective means of improving the efficiency of a synchronous reluctance motor (SynRM) drive. This paper introduces an improved approach to optimizing efficiency that treats the motor and inverter as a unified system, ensuring maximum efficiency throughout operation. Diverging from conventional id=iq or maximum torque per ampere control methods, this approach accounts for both iron losses and inverter losses, while also addressing cross-coupling effects. This is achieved through real-time virtual signal injection, which extracts optimal operation points, and an accurate analytical approach to assess iron losses. Experimental results convincingly validate the effectiveness of this novel methodology

Preparation of carbon-sensitized and Fe–Er codoped TiO2 with response surface methodology for bisphenol A photocatalytic degradation under visible-light irradiation

The carbon-sensitized and Fe–Er codoped TiO2 (Fe/Er–TiO2) was synthesized by a facile solvothermal method using titanium isopropoxide both as titanium precursor and carbon source, as well as ferric nitrate and erbium nitrate as dopants source. The response surface methodology (RSM) with central composite design (CCD) model was used to obtain the optimum synthesis conditions for this novel Fe/Er–TiO2. The RSM was also applied to study the main and interactive effects of the parameters (Er concentration [Er], Fe concentration [Fe] and calcination temperature [CT]) investigated. The experimental results indicated an improved photocatalytic activity of Fe/Er–TiO2 for bisphenol A (BPA) degradation compared to the pristine TiO2, Er–TiO2, Fe–TiO2 and Degussa P25 (P25) under visible light irradiation. In addition, the RSM model obtained (R2 = 0.929) showed a satisfactory correlation between the experimental results and predicted values of BPA removal efficiency. The identified optimum condition for preparing Fe/Er–TiO2 was 1.5 mol%, 1.25 mol% and 450 °C for [Er], [Fe] and [CT], respectively. Moreover, the photocatalytic activity of the optimized Fe/Er–TiO2 was preserved effectively even after ten cycles of use. The possible photocatalytic mechanisms induced by the Fe/Er–TiO2 under visible light irradiation are proposed. The enhanced photocatalytic activity of Fe/Er–TiO2 can be attributed to the synergistic effects of photosensitizing (Csingle bondO band), narrowed band gap and enhanced e−/h+ separation (Ti–O–Fe linkage), and upconversion luminescence property (Ti–O–Er linkage)

Structures and properties of the hydrogen-bond complexes: Theoretical studies for the coupling modes of the pyrazole–imidazole system

The calculations at the B3LYP/6-311+G* level have been performed for Pyrazole–Imidazole (Py–Im) system. Eight Py–Im complexes are found and their calculated geometric structures, relative energies, IR spectra and stabilization energies are presented. Those Py–Im complexes can be classified into single H-bond mode and double H-bond mode. The single H-bond complexes can be subdivided into N–Hcdots, three dots, centeredN mode and C–Hcdots, three dots, centeredN mode. The four single H-bond complexes are defined as SA, SB, SC, and SD and the four double H-bond complexes are defined as DA, DB, DC, and DD. SA and SB belong to the N–Hcdots, three dots, centeredN coupling mode while SC and SD belong to the C–Hcdots, three dots, centeredN coupling mode, respectively. The double H-bond coupling mode complexes can be further divided into two types. DA and DB have a N–Hcdots, three dots, centeredN type H-bond and a C–Hcdots, three dots, centeredN type H-bond and DC and DD have two C–Hcdots, three dots, centeredN type H-bonds. For the single H-bond modes and double H-bond modes, the complexes with N–Hcdots, three dots, centeredN type H-bond have stronger interactions than those with C–Hcdots, three dots, centeredN type H-bond. DB is the most stable isomer among the eight complexes. With corrections for the zero-point vibrational energies (ZPE) and basis set superposition errors (BSSE), the stabilization energy of DB is 7.60 kcal/mol at the B3LYP/6-311+G* level. The stability order of the eight Py–Im complexes is DB>DA>SB>SA>SC=SD>DD>DC. Moreover, this result is in close agreement with that of the natural bond orbital (NBO) analysis

Theoretical calculational studies on the mechanism of thermal dissociations for RN3 (R=CH3, CH3CH2, (CH3)2CH, (CH3)3C)

Mechanisms of RN3 (R=CH3, CH3CH2, (CH3)2CH, (CH3)3C) dissociations are proposed based on CAS, MP2 and B3LYP methods. The energy gaps between the ground-state reactants RN3 and the intersystem crossing (ISC) points are only a little lower than respective potential energy barriers of the spin-allowed reactions, 1RN3 → 1RN + 1N2. The ISC point, therefore, is considered as a transition state of the spin-forbidden reactions, 1RN3 → 3RN + 1N2. The methods of IRC and topological analysis of electron density are used to explain and predict the thermal dissociation pathways of the reactions studied

Studies on the structural properties of iodine-containing complexes: DFT calculations for IO–H2O and HOI–H2O systems

The calculations of geometric structures, relative energies, vibrational frequencies, infrared intensities and binding energies of six IO–H2O and three HOI–H2O complexes have been performed using the B3LYP, B3P86, B3PW91 methods at the 6-311++G(3df,3pd) basis set level. The corrections for zero-point energy (ZPE) and basis set superposition error (BSSE) of these complexes have also been considered in order to obtain accurate binding energies of these complexes. The analysis of the Natural Bond Orbital (NBO) second-order interaction energies has also been used to illuminate the binding energies and the stability of these IO–H2O and HOI–H2O complexes