Device Design Of Negative Ion Beam Source And Theoretical Study Of OCS~- Structure And Electron Affinity

Anions exist in a wide range of the nature world,the near-earth space environment(ionosphere and magnetosphere)and the magnetosphere of the other stars,which in varying degrees influence the living environment and health of human being,Anions have significantly different structures and properties compared with neutral atomic molecules,such as the short-range coulomb potential of extra electrons,the low electron affinity and the non-negligible electron correlation,etc.A further research is needed to understand the electron states of anions and its internal physical mechanisms,as there are few studies on the interaction between anions and laser pulse at present.We design a suit of experiment device,including the production and detection of anions,to study the interaction between anions and laser in this paper.An electron gun is designed all by ourselves to produce an electron beam,and then we get the anion source through the electron attachment molecule.In order to ensure that anions of sufficient density can reach the reaction zone,various parameters(dimensions and voltages)in the optimization instrument are simulated by SIMION.Finally,it is proved that the design we used to study the interaction between anions and laser pulse is reasonable through the simulated time of flight mass spectrum.The geometric structure(bond length and bond angle)and spectral parameters(vibration frequency and single point energy)of OCS molecular and OCS~-electronic states are calculated by using the unrestricted coupled cluster with singles,doubles,and perturbative triples(CCSD(T)/UCCSD(T))method,combinedwithCore-Valence correlation,Scalar relativistic effect and complete basis set(CBS).Finally,we get the electron affinity of OCS molecular between 0.075eV and 0.078eV.