Projects per year
Abstract
Recent measurements of the third harmonic scattering responses of molecules have given a new impetus for computing molecular second hyperpolarizabilities (γ) and for deducing structure-property relationships. This paper has employed a variety of wavefunction and density functional theory methods to evaluate the second hyperpolarizability of the p-nitroaniline prototypical push-pull π-conjugated molecule, addressing also numerical aspects, such as the selection of an integration grid and the impact of the order of differentiation vs the achievable accuracy by using the Romberg quadrature. The reliability of the different methods has been assessed by comparison to reference Coupled-Cluster Singles and Doubles with perturbative treatment of the Triples results. On the one hand, among wavefunction methods, the MP2 scheme offers the best accuracy/cost ratio for computing the static γ. On the other hand, using density functional theory, γ remains a challenging property to compute because all conventional, global hybrid or range-separated hybrid, exchange-correlation functionals underestimate static γ values by at least 15%. Even tuning the range-separating parameter to minimize the delocalization errors does not enable to improve the γ values. Nevertheless, the original double-hybrid B2-PLYP functional, which benefits from 27% of PT2 correlation and 53% Hartree-Fock exchange, provides accurate estimates of static γ values. Unfortunately, the best performing exchange-correlation functionals for γ are not necessarily reliable for the first hyperpolarizability, β, and vice versa. In fact, the β of p-nitroaniline (pNA) could be predicted, with a good accuracy, with several hybrid exchange-correlation functionals (including by tuning the range-separating parameter), but these systematically underestimate γ. As for γ, the MP2 wavefunction method remains the best compromise to evaluate the first hyperpolarizability of pNA at low computational cost.
Original language | English |
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Article number | 114104 |
Journal | The Journal of chemical physics |
Volume | 159 |
Issue number | 11 |
DOIs | |
Publication status | Published - 21 Sept 2023 |
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CÉCI – Consortium of high performance computing centers
CHAMPAGNE, B. (PI), Lazzaroni, R. (PI), Geuzaine , C. (CoI), Chatelain, P. (CoI) & Knaepen, B. (CoI)
1/01/18 → 31/12/22
Project: Research
Equipment
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High Performance Computing Technology Platform
Champagne, B. (Manager)
Technological Platform High Performance ComputingFacility/equipment: Technological Platform
Activities
- 2 Oral presentation
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Nonlinear Optics (NLO) day
Kaka, K. S. (Speaker)
8 Jun 2023Activity: Talk or presentation types › Oral presentation
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A Quantum Chemical Investigation of the Second Hyperpolarizability of P-nitroaniline
Kaka, K. S. (Speaker)
22 May 2023Activity: Talk or presentation types › Oral presentation
Press/Media
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University of Namur Reports Findings in Chemical Physics (A quantum chemical investigation of the second hyperpolarizability of p-nitroaniline)
Champagne, B., Beaujean, P. & Kaka, K. S.
2/10/23
1 item of Media coverage
Press/Media: Expert Comment