Studies Of Diatomic Photodissociation And The Involved Rovibrational Resonances

Photodissociation dynamics is an important branch of atomic and molecular dynam-ics.Resonance states are closely related to the photodissociation process and are one of the important roles affecting this process.With the development of experimental technology,a lot of high-precision experimental data have been measured in the field of astronomi-cal,atmospheric and environmental chemistry,laser chemistry,molecular dynamics and plasma environments.However,it’s also a great challenge for modern AMO physics to study and understand these basic photodissociation data and kinetic processes.This the-sis will carry out systematic and in-depth theoretical research on photodissociation and involved resonances,which mainly includes the following four parts.In Chapter 1,the background of this thesis was introduced,and we summarize the classification of photodissociation process and the typical theoretical research methods of resonance.In Chapter 2,we have developed an efficient theoretical calculation method or pro-gram for direct photodissociation process,taking Be H⁺system as an example,the com-plementary photodissociation cross section from X¹Σ⁺to A¹Σ⁺,B¹Πand C¹Σ⁺were provided,LTE cross sections are also shown in different temperatures.We found that shape resonances can greatly affect the direct photodissociation cross section,and were shown as many peaks of narrow structure.The relevant results have important reference significance for interstellar observations as well as the fusion plasma emissions in the edge and divertor region.In Chapter 3,we have developed an efficient theoretical calculation method for cou-pled photodissociation process,taking Be H system as an example,particularly,the nona-diabatic couplings between states 2²Σ⁺and 3²Σ⁺have been carefully studied for the re-ported rovibrationally resolved partial and full photodissociation cross sections with dif-ferent temperature.We found that the Feshbach resonance peaks in coupled process are different from the shape resonances in uncoupled case,which reveals that the Feshbach resonances caused by nonadiabatic couplings would affect the photodissociation process significantly.The relevant results have important reference significance for Be H pho-todissociation experiment as well as in ultraviolet irradiated interstellar environments.In Chapter 4,we developed the contour deformation method（CDM）for the calcula-tion of rovibrational shape and Feshbach in AMO physics for the first time.The scattering process for e-Na⁺and predissociation process for H₂-Ar system were used as single channel examples,besides,the charge transfer process for HLi^-and the scattering for HD on the surface of AgH were used as multichannel examples.The resonance parameters are given comprehensively and systematically,and the results are in good agreement with QMOCC and CSM.In the field of AMO physics,CDM could be one candidate powerful tool for studies of resonances in complex atomic and molecular systems.In Chapter 5,the relationship between the Feshbach resonances and the nonadiabatic couplings in AC region has been investigated.We found that Zhu-Nakamura parameter can be well applied to quantitatively estimate the importance of resonances in the AC region.The contributions of resonances in the AC region to the cross sections depend strongly on the coupling strength of the system.Further analysis shows that the present conclusions are essentially related to the resonance widths,that narrow resonances could exhibit strongly as sharp peaks,and broad ones would bury in the background.Example applications of the quantity for real molecules（MgH,CO,OH,O₂）can well explain the evolutions of cross sections in the AC region published in the literatures.Practically,Zhu-Nakamura parameter provides an easy way to determine the candidate molecules when studying the resonances in the AC region.Finally,the conclusions of this thesis and the research plans in future are given in Chapter 6.