State specific multireference M酶ller-Plesset perturbation theory: A few applications to ground, excited and ionized states

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• 作者：Sudip Chattopadhyay^a ; ^{sudip_chattopadhyay@rediffmail.com} ; Uttam Sinha Mahapatra^b ; ^{uttam.mahapatra@linuxmail.org} ; Rajat K. Chaudhuri^c ; ^{rkchaudh@iiap.res.in}
• 关键词：State specific multireference Mø ; ller&ndash ; Plesset perturbation theory ; Ground ; or excited/ionized states ; Spectroscopic constants ; Excitation or ionization energy
• 刊名：Chemical Physics
• 出版年：2012
• 期刊代码：18_03010104
• 类别：ch
• 出版时间：5 June, 2012
• 卷：401
• 期：Complete
• 页码：15-26
• 文件大小：428 K

摘要

We provide further tests and illustrations of the complete active space based state specific multireference M酶ller-Plesset perturbation theory (SS-MRMPPT) which opens the way for the treatment of dynamic correlations in situations containing significant static correlations also in an accurate, size- extensive and intruder free manner enjoying at the same time a very favorable computational cost. We have investigated various interesting and computationally challenging systems [H₂O, H₂O⁺, BeC, MgC, CO⁺, Be₃, benzene, trimethylenemethane and 1,2,3-tridehydrobenzene] in either their ground, or excited/ionized states. It is found that SS-MRMPPT calculations provide very encouraging results which can be meaningfully compared with other state-of-the-art theoretical estimates. Present results convincingly indicate that the SS-MRMPPT method is not only successful in portraying situations that warrant MR description but also performs acceptably good in cases where a naive single-reference method is enough which reinforces the claim that the SS-MRMPPT is a very useful and flexible ab initio method.