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Abstract
The linear [χ^{(1)}] and secondorder nonlinear [χ^{(2)}] optical susceptibilities of the 2methyl4nitroaniline (MNA) crystal are calculated within the local field theory, which consists of first computing the molecular properties, accounting for the dressing effects of the surroundings, and then taking into account the local field effects. Several aspects of these calculations are tackled with the aim of monitoring the convergence of the χ^{(1)} and χ^{(2)} predictions with respect to experiment by accounting for the effects of (i) the dressing field within successive approximations, of (ii) the firstorder ZPVA corrections, and of (iii) the geometry. With respect to the reference CCSDbased results, besides double hybrid functionals, the most reliable exchangecorrelation functionals are LCBLYP for the static χ^{(1)} and CAMB3LYP (and M052X, to a lesser extent) for the dynamic χ^{(1)} but they strongly underestimate χ^{(2)}. Double hybrids perform better for χ^{(2)} but not necessarily for χ^{(1)}, and, moreover, their performances are much similar to MP2, which is known to slightly overestimate β, with respect to highlevel coupledclusters calculations and, therefore, χ^{(2)}. Other XC functionals with less HF exchange perform poorly with overestimations/underestimations of χ^{(1)}/ χ^{(2)}, whereas the HF method leads to underestimations of both. The firstorder ZPVA corrections, estimated at the B3LYP level, are usually small but not negligible. Indeed, after ZPVA corrections, the molecular polarizabilities and first hyperpolarizabilities increase by 2% and 5%, respectively, whereas their impact is magnified on the macroscopic responses with enhancements of χ^{(1)} by up to 5% and of χ^{(2)} by as much as 10%12% at λ = 1064 nm. The geometry plays also a key role in view of predicting accurate susceptibilities, particularly for pushpull πconjugated compounds such as MNA. So, the geometry optimized using periodic boundary conditions is characterized by an overestimated bond length alternation, which gives larger molecular properties and even larger macroscopic responses, because of the local field factor amplification effects. Our best estimates based on experimental geometries, charge dressing field, ZPVA correction, and CCSD molecular properties lead to an overestimation of χ^{(1)} by 12% in the static limit and 7% at λ = 1064 nm. For χ^{(2)}, the difference, with respect to the experiment, is satisfactory and of the order of one standard deviation.
Original language  English 

Pages (fromto)  21142124 
Number of pages  11 
Journal  Journal of Chemical Theory and Computation 
Volume  10 
Issue number  5 
DOIs  
Publication status  Published  2014 
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Dive into the research topics of 'Evaluation of the Linear and SecondOrder NLO Properties of Molecular Crystals within the Local Field Theory: Electron Correlation Effects, Choice of XC Functional, ZPVA Contributions, and Impact of the Geometry in the Case of 2Methyl4nitroaniline: Electron correlation effects, choice of XC functional, ZPVA contributions, and impact of the geometry in the case of 2methyl4nitroaniline'. Together they form a unique fingerprint.

PAI n°P7/05  FS2: Functional Supramolecular Systems (FS2)
CHAMPAGNE, B., De Vos, D., Van der Auweraer, M., Jérôme, C., Lazzaroni, R., Marin, G., Jonas, A., Du Prez, F., Vanderzande, D., Van Tendeloo, G., Van Speybroeck, V., NENON, S. & STAELENS, N.
1/04/12 → 30/09/17
Project: Research
Equipment

High Performance Computing Technology Platform
Benoît Champagne (Manager)
Technological Platform High Performance ComputingFacility/equipment: Technological Platform