Challenging compounds for calculating molecular second hyperpolarizabilities: the triplet state of the trimethylmethane diradical and two derivatives

Marc De Wergifosse, Benoît Champagne, Soichi Ito, Kotaro Fukuda, Masayoshi Nakano

Résultats de recherche: Contribution à un journal/une revueArticle

Résumé

The second hyperpolarizability g of trimethylenemethane (TMM) and two 1,3-dipole derivatives (NXA and OXA) in their triplet ground state has been evaluated at the UCCSD(T) level with the d-aug-cc-pVDZ extended basis set, highlighting that g decreases from TMM to NXA and OXA, following the opposite order of their permanent dipole moments. These results are then used to benchmark a broad range of levels of approximation. So, the UMP2, UMP4, and UCCSD methods can be used to characterize g of TMM and NXA but not of OXA. In that case, the large field-induced charge transfer contribution is difficult to handle using the MPn methods and only the UCCSD method provides values close to the UCCSD(T) reference. Turning to the performance of DFT with typical exchange–correlation functionals, the UM06-2X functional, which contains 54% of HF exchange, performs very well with a maximum of 4.5% of difference with respect to the reference values. On the other hand, employing less HF exchange leads to an overestimation of the responses whereas range-separated hybrids generally underestimate the second hyperpolarizabilities. Finally, the use of spin-projected methods for these 1,3-dipole triplet molecules has a little impact since the spin contamination is almost negligible.
langue originaleAnglais
Pages (de - à)6420
Nombre de pages6429
journalPhysical Chemistry Chemical Physics
Volume18
Les DOIs
étatPublié - 2016

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@article{96b50d3459444a5290cc41252d38c9d8,
title = "Challenging compounds for calculating molecular second hyperpolarizabilities: the triplet state of the trimethylmethane diradical and two derivatives",
abstract = "The second hyperpolarizability g of trimethylenemethane (TMM) and two 1,3-dipole derivatives (NXA and OXA) in their triplet ground state has been evaluated at the UCCSD(T) level with the d-aug-cc-pVDZ extended basis set, highlighting that g decreases from TMM to NXA and OXA, following the opposite order of their permanent dipole moments. These results are then used to benchmark a broad range of levels of approximation. So, the UMP2, UMP4, and UCCSD methods can be used to characterize g of TMM and NXA but not of OXA. In that case, the large field-induced charge transfer contribution is difficult to handle using the MPn methods and only the UCCSD method provides values close to the UCCSD(T) reference. Turning to the performance of DFT with typical exchange–correlation functionals, the UM06-2X functional, which contains 54{\%} of HF exchange, performs very well with a maximum of 4.5{\%} of difference with respect to the reference values. On the other hand, employing less HF exchange leads to an overestimation of the responses whereas range-separated hybrids generally underestimate the second hyperpolarizabilities. Finally, the use of spin-projected methods for these 1,3-dipole triplet molecules has a little impact since the spin contamination is almost negligible.",
author = "{De Wergifosse}, Marc and Beno{\^i}t Champagne and Soichi Ito and Kotaro Fukuda and Masayoshi Nakano",
year = "2016",
doi = "10.1039/c5cp06547j",
language = "English",
volume = "18",
pages = "6420",
journal = "Physical chemistry chemical physics : PCCP",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",

}

TY - JOUR

T1 - Challenging compounds for calculating molecular second hyperpolarizabilities: the triplet state of the trimethylmethane diradical and two derivatives

AU - De Wergifosse, Marc

AU - Champagne, Benoît

AU - Ito, Soichi

AU - Fukuda, Kotaro

AU - Nakano, Masayoshi

PY - 2016

Y1 - 2016

N2 - The second hyperpolarizability g of trimethylenemethane (TMM) and two 1,3-dipole derivatives (NXA and OXA) in their triplet ground state has been evaluated at the UCCSD(T) level with the d-aug-cc-pVDZ extended basis set, highlighting that g decreases from TMM to NXA and OXA, following the opposite order of their permanent dipole moments. These results are then used to benchmark a broad range of levels of approximation. So, the UMP2, UMP4, and UCCSD methods can be used to characterize g of TMM and NXA but not of OXA. In that case, the large field-induced charge transfer contribution is difficult to handle using the MPn methods and only the UCCSD method provides values close to the UCCSD(T) reference. Turning to the performance of DFT with typical exchange–correlation functionals, the UM06-2X functional, which contains 54% of HF exchange, performs very well with a maximum of 4.5% of difference with respect to the reference values. On the other hand, employing less HF exchange leads to an overestimation of the responses whereas range-separated hybrids generally underestimate the second hyperpolarizabilities. Finally, the use of spin-projected methods for these 1,3-dipole triplet molecules has a little impact since the spin contamination is almost negligible.

AB - The second hyperpolarizability g of trimethylenemethane (TMM) and two 1,3-dipole derivatives (NXA and OXA) in their triplet ground state has been evaluated at the UCCSD(T) level with the d-aug-cc-pVDZ extended basis set, highlighting that g decreases from TMM to NXA and OXA, following the opposite order of their permanent dipole moments. These results are then used to benchmark a broad range of levels of approximation. So, the UMP2, UMP4, and UCCSD methods can be used to characterize g of TMM and NXA but not of OXA. In that case, the large field-induced charge transfer contribution is difficult to handle using the MPn methods and only the UCCSD method provides values close to the UCCSD(T) reference. Turning to the performance of DFT with typical exchange–correlation functionals, the UM06-2X functional, which contains 54% of HF exchange, performs very well with a maximum of 4.5% of difference with respect to the reference values. On the other hand, employing less HF exchange leads to an overestimation of the responses whereas range-separated hybrids generally underestimate the second hyperpolarizabilities. Finally, the use of spin-projected methods for these 1,3-dipole triplet molecules has a little impact since the spin contamination is almost negligible.

U2 - 10.1039/c5cp06547j

DO - 10.1039/c5cp06547j

M3 - Article

VL - 18

SP - 6420

JO - Physical chemistry chemical physics : PCCP

JF - Physical chemistry chemical physics : PCCP

SN - 1463-9076

ER -