PMID- 21950849
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20120110
LR  - 20110928
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 135
IP  - 11
DP  - 2011 Sep 21
TI  - Zero field splitting of the chalcogen diatomics using relativistic correlated 
      wave-function methods.
PG  - 114106
LID - 10.1063/1.3636084 [doi]
AB  - The spectrum arising from the (pi*)(2) configuration of the chalcogen dimers, 
      namely, the X(2)1, a2, and b0(+) states, is calculated using wave-function theory 
      based methods. Two-component (2c) and four-component (4c) multireference 
      configuration interaction (MRCI) and Fock-space coupled cluster (FSCC) methods 
      are used as well as two-step methods spin-orbit complete active space 
      perturbation theory at 2nd order (SO-CASPT2) and spin-orbit difference dedicated 
      configuration interaction (SO-DDCI). The energy of the X(2)1 state corresponds to 
      the zero-field splitting of the ground state spin triplet. It is described with 
      high accuracy by the 2- and 4-component methods in comparison with experiment, 
      whereas the two-step methods give about 80% of the experimental values. The b0(+) 
      state is well described by 4c-MRCI, SO-CASPT2, and SO-DDCI, but FSCC fails to 
      describe this state and an intermediate Hamiltonian FSCC ansatz is required. The 
      results are readily rationalized by a two-parameter model; Deltaepsilon, the pi* spinor 
      splitting by spin-orbit coupling and K, the exchange integral between the pi(1)* 
      and the pi(-1)* spinors with, respectively, angular momenta 1 and -1. This model 
      holds for all systems under study with the exception of Po(2).
FAU - Rota, J-B
AU  - Rota JB
AD  - Laboratoire de Chimie, Ecole Normale Superieure de Lyon, 46 allee d'Italie 69364 
      Lyon Cedex 07, France.
FAU - Knecht, S
AU  - Knecht S
FAU - Fleig, T
AU  - Fleig T
FAU - Ganyushin, D
AU  - Ganyushin D
FAU - Saue, T
AU  - Saue T
FAU - Neese, F
AU  - Neese F
FAU - Bolvin, H
AU  - Bolvin H
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
EDAT- 2011/09/29 06:00
MHDA- 2011/09/29 06:01
CRDT- 2011/09/29 06:00
PHST- 2011/09/29 06:00 [entrez]
PHST- 2011/09/29 06:00 [pubmed]
PHST- 2011/09/29 06:01 [medline]
AID - 10.1063/1.3636084 [doi]
PST - ppublish
SO  - J Chem Phys. 2011 Sep 21;135(11):114106. doi: 10.1063/1.3636084.