PMID- 30037241
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20180725
LR  - 20180725
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 149
IP  - 3
DP  - 2018 Jul 21
TI  - Excitation energies from diffusion Monte Carlo using selected configuration 
      interaction nodes.
PG  - 034108
LID - 10.1063/1.5041327 [doi]
AB  - Quantum Monte Carlo (QMC) is a stochastic method that has been particularly 
      successful for ground-state electronic structure calculations but mostly 
      unexplored for the computation of excited-state energies. Here, we show that 
      within a Jastrow-free QMC protocol relying on a deterministic and systematic 
      construction of nodal surfaces using selected configuration interaction (sCI) 
      expansions, one is able to obtain accurate excitation energies at the fixed-node 
      diffusion Monte Carlo (FN-DMC) level. This evidences that the fixed-node errors 
      in the ground and excited states obtained with sCI wave functions cancel out to a 
      large extent. Our procedure is tested on two small organic molecules (water and 
      formaldehyde) for which we report all-electron FN-DMC calculations. For both the 
      singlet and triplet manifolds, accurate vertical excitation energies are obtained 
      with relatively compact multideterminant expansions built with small (typically 
      double-zeta) basis sets.
FAU - Scemama, Anthony
AU  - Scemama A
AUID- ORCID: 0000000349557136
AD  - Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse, CNRS, UPS, 
      Toulouse, France.
FAU - Benali, Anouar
AU  - Benali A
AUID- ORCID: 0000000221330338
AD  - Computational Science Division, Argonne National Laboratory, Argonne, Illinois 
      60439, USA.
FAU - Jacquemin, Denis
AU  - Jacquemin D
AD  - Laboratoire CEISAM-UMR CNRS 6230, Universite de Nantes, 2 Rue de la Houssiniere, 
      BP 92208, 44322 Nantes Cedex 3, France.
FAU - Caffarel, Michel
AU  - Caffarel M
AUID- ORCID: 0000000332676809
AD  - Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse, CNRS, UPS, 
      Toulouse, France.
FAU - Loos, Pierre-Francois
AU  - Loos PF
AD  - Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse, CNRS, UPS, 
      Toulouse, France.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
EDAT- 2018/07/25 06:00
MHDA- 2018/07/25 06:01
CRDT- 2018/07/25 06:00
PHST- 2018/07/25 06:00 [entrez]
PHST- 2018/07/25 06:00 [pubmed]
PHST- 2018/07/25 06:01 [medline]
AID - 10.1063/1.5041327 [doi]
PST - ppublish
SO  - J Chem Phys. 2018 Jul 21;149(3):034108. doi: 10.1063/1.5041327.