Ab Initio Study Of Spectral Constants And Anharmonic Fields Of HnXO(X=As, P; N=1,2)

Atomic and molecular physics is the secondary subjects in the field of physics.Ab initio method is widely used in the field of atomic and molecular physics and is an important means to obtain the information of architecture and dynamics.Various spectral constants of molecules can be determined by ab initio calculation of the nonresonant field.The study of molecular spectra can reveal the internal structure,movement law and physical and chemical characteristics of molecules,and can obtain the accurate information of rotational energy level,vibration energy level and electronic energy level of molecules,so as to accurately determine the nuclear distance,vibration frequency,force constant,dissociation energy and other data related to molecular structure.Active intermediates resulting from chemical vapor deposition in the semiconductor industry and organometallic chemical vapor deposition reactions.The application of n=1,2)to the electronic properties of semiconductor materials has attracted wide attention.In this paper,we study four molecules of the vast system,HnXO?X=As,P;N=1,2?.HnXO?X=As,P;N=1,2?play an important role in the chemical vapor deposition?CVD?or metal-organic chemical vapor deposition?MOCVD?processes of the semiconductor industry.As a reactive intermediate generated in CVD or MOCVD processes,the HAsO and H₂AsO moleculeas can be used to modify the electronic characteristics of semiconducting materials.As one of the common third-row atoms expected oxygen,the atom P plays an important role on planetary bodies or in its atmospheres.The HPO molecule is interesting because it may be a good candidate for a phosphorus-containing molecule to search for in the interstellar medium.The HPO molecule,an important intermediate in the oxidation of phosphine that led to the formation of phosphoric acid,has also been identified as one of the emitting species in the still incompletely understood problem.Although various fatty and aromatic organic derivatives of H₂PO can easily be photolyzed into solids or solutions and have been studied by ESR spectrum,their spectral properties in the gas phase have not been explored.So,As a reactive intermediate the HnXO?X=As,P;N=1,2?produced in the process of chemical vapor deposition reaction have attracted people's interest.Hence,for further study of the HnXO?X=As,P;N=1,2?rotational spectrum,The main working conditions of this paper is as follows:Considering the problems of transient molecular life,energy level degeneracy and instrument resolution,it is difficult to measure the vibration spectrum experimentally,so it is necessary to study the vibration spectrum theoretically.Density functional theory?DFT?and second-order M?ller-Plesset?MP2?methods with the basis sets of cc-pVQZ and cc-pV5Zor aug-cc-pVQZ and aug-cc-pV5Z are employed to study the equilibrium geometries,spectroscopic constants and anharmonic force fields of HnXO?X=As,P;N=1,2?and predict the constants that had not been reported by experimental theory.First,B3LYP,B3P86,B3PW91 and the second-order M?ller-PlessetMP2 methods were used to study the anharmonic force field and spectral constant of the ground state for HAsO molecular.The computed molecular geometries,rotational constants,and vibrational frequencies constant are compared with the corresponding experimental results.The results show that the theoretical calculation results of B3LYP/cc-pV5Z are in good agreement with the experimental results.On this basis,we use the B3LYP/cc-pV5Z theoretical level to make reliable predictions for the the predicted anharmonic force field,centrifugal distortion constants,vibration-rotation interaction constants,and Coriolis coupling constants of HAsO molecules.Secondly,density functional theory B3LYP,B3P86,B3PW91 and MP2 with aug-cc-pVQZ and aug-cc-pV5Z basis sets were used to study the anharmonic force field and spectral constant of the ground state for H₂AsO molecules.The geometric structure,ground state rotation constant,vibrational frequencies and anharmonic constant calculatedbyB3PW91/aug-cc-pv5zareconsistentwiththeexperimental data.Therefore,the fundamental frequency,vibration-rotation interaction constant,four-time six-time centrifugal distortion constant,coriolis coupling constant and the cubic and quartic force constant obtained by using this theoretical level are closer to the real value and can be used as theoretical prediction.Finally,B3LYP,B3PW91,B3P86 and MP2 methods were used to optimize the HPO geometric structure with the cc-pVQZ and aug-cc-pV5Z basis sets,and the obtained optimization structure was in good agreement with the existing theoretical values.On the basis of the optimized geometric structure,we theoretically calculated the HPO and H₂PO geometric structure?including bond length and bond Angle?,spectral constant and the anharmonic force field for theoretical calculation.From the calculation results,it is found that the theoretical values obtained by B3PW91/cc-pVQZ for calculating the spectral constant and the anharmonic force field of HPO molecules are in good agreement with the existing relevant experiments.The H₂PO results calculated by B3P86 method are closer to the experimental values,and the constants not reported by experimental theory are reasonably predicted.