基于非谐力场的HOI分子振动光谱研究  

The Theoretical Study of Anharmonic Vibrational Spectra of HOI

作　　者：陈恒杰[1] 王全武[1] 张家伟[1] 望军[2] CHEN Heng-jie;WANG Quan-wu;ZHANG Jia-wei;WANG Jun(School of Mathematics and Physics,Chongqing University of Science and Technology,Chongqing 401331,China;School of Metallurgy and Matericals Engineering,Chongqing University of Science and Technology,Chongqing 401331,China)

机构地区：[1]重庆科技学院数理学院,重庆401331 [2]重庆科技学院冶金与材料工程学院,重庆401331

出　　处：《光谱学与光谱分析》2018年第9期2665-2671,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(11347024);重庆市科委自然科学基金项目(cstc2014jcyjA50010;cstc2014jcyjA00030);重庆市教委科学技术研究项目(KJ1601332;KJ1401313)资助

摘　　要：应用包含非迭代三激发(CCSD(T))、迭代三激发(CC3)及其变体(CCSDT-3)的耦合簇理论(CC)和密度泛函理论(DFT)之B3LYP方法,使用直到五阶的自洽相关一致基组aug-cc-pVxZ/aug-cc-pVxZ-PP(x=T,Q,5),首先优化出HOI的平衡结构,接着在该结构附近采样势能点并将其在简正坐标下拟合成直到四阶的多项式力场,依据该力场结合振动自洽场(VSCF)、振动组态相互作用(VCI)和二阶振动微扰理论(VPT2)进行非谐振动分析,精确预期了HOI的基频、直到v_1+v_2+v_3=3的和频与倍频,得到其转动常数、旋振相互作用常数、非谐性常数和离心畸变常数,同时振子强度被估计,氘取代效应被进一步考察。结果表明:当前计算值与已知实验结果符合良好,其中耦合簇理论计算的振动光谱常数更加可靠,DFT误差明显偏大,但两者计算的振动频率却相当一致;并非基组越大,计算得到的非谐振动常数/频率与实验更符合,总体来讲CC3和CCSDT-3的结果更值得信赖;HOI/DOI都没有共振发生。The structure of the HOI molecule was optimized at first,by employing the coupledcluster theory(CC)with single,double,and perturbative triple excitations(CCSD(T)),the iterative triple excitations(CC3)and its variants(CCSDT-3),and the B3LYP method from the density functional theory(DFT)in conjunct with the Dunning’s correlation consistent basis sets aug-cc-pV x Z/aug-cc-pV xZ-PP(x=T,Q,5).Then,a series of discrete potential energy points were extracted nearby the equilibrium structure,which have been fitted to fourth-order polynominal expansion force field in normal coordinate.In addition,the anharmonic vibrational analysis were performed by the vibrational self-consistent field(VSCF),the vibrational configuration interaction(VCI)and the second-order vibrational perturbation theory(VPT2),the fundamental,overtoneand combination(v 1+v 2+v 3=3),the rotational constants,the vibrational-rotational interaction constants,anharmonic constants,centrifugal distortion constants have been expected,the oscillator strength has been evaluated,and the effect of Deuterium substitution was investigated.The results showthat:first,the present calculated values are in good agreement with available experimental results,spectroscopic constants from coupled cluster theory(CC)are more reliable than DFT,the deviation from DFT is obviously large,but it is quite consistent with the vibrational frequencies between CC and DFT;Second,it is not the larger basis set that causes the better coincidence betweencalculations and experiments,in general,the CC3 and CCSDT-3 results are more credible.Third,there is no resonance occurred in HOI or DOI.

关 键 词：HOI 振动谱 非谐性力场 VPT2/VCI/VSCF 耦合簇理论 

分 类 号：O561.3[理学—原子与分子物理]