01908nas a2200181   4500008004100000022001400041245007000055210006700125260000800192300001600200490000800216520132900224100002401553700001501577700001601592700001801608856010001626       2020                        eng d  a1089-563900aNegative ion resonance states: the fock-space coupled-cluster way0 aNegative ion resonance states the fockspace coupledcluster way  cDEC  a10407-104210 v1243 a<p>The negative ion resonance states, which are electron-molecule metastable compound states, play the most important role in free-electron controlled molecular reactions and low-energy free-electron-induced DNA damage. Their electronic structure is often only poorly described but crucial to an understanding of their reaction dynamics. One of the most important challenges to current electronic structure theory is the computation of negative ion resonance states. As a major step forward, coupled-cluster theories, which are well-known for their ability to produce the best approximate bound state electronic eigen solutions, are upgraded to offer the most accurate and effective approximations for negative ion resonance states. The existing Fock-space coupled-cluster (FSCC) and the equation-of-motion coupled-cluster (EOM-CC) approaches that compute bound states are redesigned for the direct and simultaneous determination of both the kinetic energy of the free electron at which the electron-molecule compound states are resonantly formed and the corresponding autodetachment decay rate of the electron from the metastable compound state. This Feature Article reviews the computation of negative ion resonances using the FSCC approach and, in passing, provides the highlights of the equivalent EOM-CC approach.</p>
1 aBasumallick, Suhita1 aSajeev, Y.1 aPal, Sourav1 aVaval, Nayana  uhttps://library.ncl.res.in/content/negative-ion-resonance-states-fock-space-coupled-cluster-way