01512nas a2200169   4500008004100000022001400041245014100055210006900196260012500265300001100390490000800401520076400409100001401173700001401187700001101201856013001212       2005                        eng d  a0021-960600aAnalytically continued Fock space multireference coupled-cluster theory: application to the (2)Pi(g) shape resonance in e-N-2 scattering0 aAnalytically continued Fock space multireference coupledcluster   aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScJUN  a2343200 v1223 a<p>The technique of Fock space multireference coupled-cluster (FSMRCC) is applied for the first time to the correlated calculation of the energy and width of a shape resonance in an electron-molecule collision. The procedure is based upon combining a complex absorbing potential with FSMRCC theory. Accurate resonance parameters are obtained by solving a small non-Hermitian eigenvalue problem. The potential-energy curve of the (2)Pi(g) state of N-2(-) is calculated using the FSMRCC and multireference configuration-interaction (MRCI) level of theories. Comparison with the single-determinant Hartree-Fock theory indicates that correlation effects are important in determining the behavior of the resonance state. (C) 2005 American Institute of Physics.</p>1 aSajeev, Y1 aSantra, R1 aPal, S  uhttps://library.ncl.res.in/content/analytically-continued-fock-space-multireference-coupled-cluster-theory-application-2pig-101939nas a2200169   4500008004100000022001400041245009200055210006900147260012500216300001100341490000800352520124500360100001401605700001401619700001101633856012501644       2005                        eng d  a0021-960600aCorrelated complex independent particle potential for calculating electronic resonances0 aCorrelated complex independent particle potential for calculatin  aCIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USAbAMER INST PHYSICScNOV  a2041100 v1233 a<p>We have formulated and applied an analytic continuation method for the recently formulated correlated independent particle potential [A. Beste and R. J. Bartlett J. Chem. Phys. 120, 8395 (2004)] derived from Fock space multireference coupled cluster theory. The technique developed is an advanced ab initio tool for calculating the properties of resonances in the low-energy electron-molecule collision problem. The proposed method quantitatively describes elastic electron-molecule scattering below the first electronically inelastic threshold. A complex absorbing potential is utilized to define the analytic continuation for the potential. A separate treatment of electron correlation and relaxation effects for the projectile-target system and the analytic continuation using the complex absorbing potential is possible, when an approximated form of the correlated complex independent particle potential is used. The method, which is referred to as complex absorbing potential-based correlated independent particle (CAP-CIP), is tested by application to the well-known (2)Pi(g) shape resonance of e-N-2 and the B-2(2g) shape resonance of e-C2H4 (ethylene) with highly satisfactory results. (c) 2005 American Institute of Physics.</p>1 aSajeev, Y1 aSantra, R1 aPal, S  uhttps://library.ncl.res.in/content/correlated-complex-independent-particle-potential-calculating-electronic-resonances-1