Energy gradient method for the ground , excited , ionized , and ž electron - attached states calculated by the SAC symmetry - adapted / ž / cluster r SAC – CI configuration interaction method
نویسندگان
چکیده
A method for calculating the analytical energy gradient of the ground, excited, ionized, and electron-attached states Ž . Ž . calculated by the SAC symmetry-adapted cluster rSAC–CI configuration interaction method was formulated and implemented. This method adapts to the selection procedure of the linked and unlinked operators in the current SACrSAC–CI code. It was applied to various molecules in various electronic states, and was confirmed to perform well for general use. q 1999 Elsevier Science B.V. All rights reserved.
منابع مشابه
Analytical energy gradient of the ground, excited, ionized and electron-attached states calculated by the SACrSAC-CI method
The method of calculating the analytical energy gradients for the ground, excited, ionized and electron-attached states Ž . Ž . calculated by the SAC symmetry adapted cluster rSAC-CI configuration interaction method is formulated and implemented. It is adapted with the configuration selection procedure used in the SACrSAC-CI method. The performance of the method is investigated for the Li and C...
متن کاملFormulation and implementation of direct algorithm for the symmetry-adapted cluster and symmetry-adapted cluster-configuration interaction method.
We present a new computational algorithm, called direct algorithm, for the symmetry-adapted cluster (SAC) and SAC-configuration interaction (SAC-CI) methodology for the ground, excited, ionized, and electron-attached states. The perturbation-selection technique and the molecular orbital index based direct sigma-vector algorithm were combined efficiently with the use of the sparse nature of the ...
متن کاملElectronic excitation and ionization spectra of azabenzenes: Pyridine revisited by the symmetry-adapted cluster configuration interaction method
Electronic excited and ionized states of pyridine were reinvestigated by the symmetry-adapted cluster configuration interaction ~SAC-CI! method using an extended basis set and a wide active space. The present SAC-CI results for the singlet and triplet excited states are greatly improved and agree well with the experimental observations, providing a firm assignment of all low-lying n→p* and p→p*...
متن کاملGround and excited states of singlet, cation doublet, and anion doublet states of o-benzoquinone: a theoretical study.
The singlet excited states and doublet ionized/electron-attached states of o-benzoquinone (o-BQ) were studied by the symmetry adapted cluster (SAC)/SAC-configuration interaction (SAC-CI) method, and the corresponding spectral bands were assigned. The calculated transition energies reasonably reproduced the experimental spectra with the mean error of about 0.2 eV, except for the 1 1A1 states, wh...
متن کاملTheoretical study of the singlet and triplet vertical electronic transitions of styrene by the symmetry adapted cluster-configuration interaction method
The ground state, singlet! singlet and singlet! triplet vertical excited states of styrene have been studied by using the symmetry adapted cluster-configuration interaction (SAC-CI) method with aug-cc-pVDZ basis sets supplemented with molecule-centered Rydberg functions. The characteristic structures of the bands observed in the vacuum ultraviolet (VUV) and electron energy loss (EEL) spectra ha...
متن کامل