Applications of level shift corrected perturbation theory in electronic spectroscopy

Roos, Björn O.; Andersson, Kerstin; Fülscher, Markus P.; Serrano‐Andrés, Luis; Pierloot, Kristine; Merchán, Manuela; Molina, Vicent

doi:10.1016/s0166-1280(96)80039-x

Cited by 188 publications

(159 citation statements)

References 20 publications

Supporting

Mentioning

151

Contrasting

Unclassified

Order By: Relevance

“…A linear-least squares fit between the experimental and calculated data, in energy space, gives a common adjustment parameter of −3350 cm −1 , which when applied to the raw CASPT2 spectra gives the shifted curves that are also shown in Figure 2 and are in much better quantitative agreement with experiment. This shift of the CASPT2 spectra in comparison to experiment is in line with the normal error bar for CASPT2 excitation energies (≈ 0.3 eV) [50].…”

Section: Ab Initio Spectrasupporting

confidence: 87%

Theoretical Modeling of Low‐Energy Electronic Absorption Bands in Reduced Cobaloximes

Bhattacharjee¹,

Chavarot‐Kerlidou²,

Dempsey³

et al. 2014

ChemPhysChem

View full text Add to dashboard Cite

The reduced Co(I) states of cobaloximes are powerful nucleophiles that play an important role in the hydrogen-evolving catalytic activity of these species. In this work we have analyzed the low energy electronic absorption bands of two cobaloxime systems experimentally and using a variety of density functional theory and molecular orbital ab initio quantum chemical approaches. Overall we find a reasonable qualitative understanding of the electronic excitation spectra of these compounds but show that obtaining quantitative results remains a challenging task. KeywordsCobaloxime complexes; H 2 evolving catalysts; theoretical electronic spectra; vitamin B 12 mimics IntroductionCobaloximes are pseudo-macrocyclic bis(dialkylglyoximato) cobalt complexes, first developed in the seventies as vitamin B 12 mimics. This family of complexes has become of * martin.field@ibs.fr. Europe PMC Funders GroupAuthor Manuscript Chemphyschem. Author manuscript; available in PMC 2015 August 10. Published in final edited form as:Chemphyschem. [3,4,5] of their promising hydrogen-evolving catalytic capability. Today, cobaloximes, and the related diimine-dioxime cobalt complexes [6,7,8,9], are recognized as some of the most efficient molecular catalysts for electro-and photo-catalytic hydrogen evolution [10,11,12]. These compounds are known to be powerful nucleophiles in their reduced Co(I) state. It is accepted that the catalytic cycle for hydrogen evolution proceeds via protonation of the Co(I) species, yielding a Co(III)-H hydridocobaloxime intermediate that, after further reduction to the Co(II)-H state, can evolve dihydrogen through either protonation of the hydride moiety or bimolecular reductive elimination [1,2,3,4,5,10,11,6,13,14,15,16,17,18].Recent reports from the groups of Muckerman [19], and Jiang [21] have addressed aspects of the catalytic activity of these compounds using quantum chemical approaches and confirm the role of the Co(I) species. Experimentally, the spectroscopic signatures of Co(I) intermediates have been observed during the course of electro-and photo-catalytic experiments [4,5,22], and the Co(I) species [14,23,24,9], and its protonated Co(III)-H form [25,26,27] Figure 1). We have employed both time-dependent density functional theory (TDDFT) and correlated molecular orbital methods to characterize the electronic excitation spectra of these compounds and show that a reasonable qualitative description of them can be obtained. Methods CalculationsThe ORCA [28] program (version 2.9) was employed for all DFT and TDDFT calculations. Geometry optimizations were performed at the DFT level using the BP86 [29,30] and B3LYP [31,32] functionals. Test calculations were also carried out with the addition of empirical van der Waals corrections [33] on compound 2 but the effects were found to be small and so will not be considered further here. To be precise, the relative ordering of the energies of the different isomers remained unchanged and the RMS heavy atom coordinate differences between equivalent optimized st...

show abstract

Section: Ab Initio Spectrasupporting

confidence: 87%

Theoretical Modeling of Low‐Energy Electronic Absorption Bands in Reduced Cobaloximes

Bhattacharjee¹,

Chavarot‐Kerlidou²,

Dempsey³

et al. 2014

ChemPhysChem

View full text Add to dashboard Cite

show abstract

“…These have previously been shown to lead to accurate multi-reference perturbation methods which do not suffer from the intruder state problems plaguing CASPT2. 66,67 Concretely, Dyall's Hamiltonian 64 is given bŷ…”

Section: Definitions Ofĥ0mentioning

confidence: 99%

Combining Internally Contracted States and Matrix Product States To Perform Multireference Perturbation Theory

Sharma

Knizia

Guo

et al. 2017

J. Chem. Theory Comput.

View full text Add to dashboard Cite

We present two efficient and intruder-free methods for treating dynamic correlation on top of general multi-configuration reference wave functions-including such as obtained by the density matrix renormalization group (DMRG) with large active spaces. The new methods are the second order variant of the recently proposed multi-reference linearized coupled cluster method (MRLCC) [S. Sharma, A. Alavi, J. Chem. Phys. 143, 102815 (2015)], and of N-electron valence perturbation theory (NEVPT2), with expected accuracies similar to MRCI+Q and (at least) CASPT2, respectively. Great efficiency gains are realized by representing the first-order wave function with a combination of internal contraction (IC) and matrix product state perturbation theory (MPSPT). With this combination, only third order reduced density matrices (RDMs) are required. Thus, we obviate the need for calculating (or estimating) RDMs of fourth or higher order; these had so far posed a severe bottleneck for dynamic correlation treatments involving the large active spaces accessible to DMRG. Using several benchmark systems, including first and second row containing small molecules, Cr2, pentacene and oxo-Mn(Salen), we shown that active spaces containing at least 30 orbitals can be treated using this method. On a single node, MRLCC2 and NEVPT2 calculations can be performed with over 550 and 1100 virtual orbitals, respectively. We also critically examine the errors incurred due to the three sources of errors introduced in the present implementation -calculating second order instead of third order energy corrections, use of internal contraction and approximations made in the reference wavefunction due to DMRG.

show abstract

“…Tentatively, such a behavior can be attributed to the fact that configurations from the expansion set generated by single and double excitations from the reference state (i.e., the CASPT2 first-order wave function) with energies close to the reference CASSCF energy will lead to an overestimation or even singularities of the perturbation energy. 74,75 As perturbation theory holds only for small perturbations, such configurations should be included already in the preceding CASSCF calculation. Thus, the exclusion from the active space of valence π-orbitals which give rise to excited states within the energy window of interest is likely to lead to an overestimation of the CASPT2 energies of the corrected states.…”

Section: Calibration Of Adenine Monomer and Homodimer Calculationsmentioning

confidence: 99%

Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

Nenov

Giussani

Segarra‐Martí

et al. 2015

The Journal of Chemical Physics

102

View full text Add to dashboard Cite

Pump-probe electronic spectroscopy using femtosecond laser pulses has evolved into a standard tool for tracking ultrafast excited state dynamics. Its two-dimensional (2D) counterpart is becoming an increasingly available and promising technique for resolving many of the limitations of pump-probe caused by spectral congestion. The ability to simulate pump-probe and 2D spectra from ab initio computations would allow one to link mechanistic observables like molecular motions and the making/breaking of chemical bonds to experimental observables like excited state lifetimes and quantum yields. From a theoretical standpoint, the characterization of the electronic transitions in the visible (Vis)/ultraviolet (UV), which are excited via the interaction of a molecular system with the incoming pump/probe pulses, translates into the determination of a computationally challenging number of excited states (going over 100) even for small/medium sized systems. A protocol is therefore required to evaluate the fluctuations of spectral properties like transition energies and dipole moments as a function of the computational parameters and to estimate the effect of these fluctuations on the transient spectral appearance. In the present contribution such a protocol is presented within the framework of complete and restricted active space self-consistent field theory and its second-order perturbation theory extensions. The electronic excited states of adenine have been carefully characterized through a previously presented computational recipe [Nenov et al., Comput. Theor. Chem. 1040-1041, 295-303 (2014]. A wise reduction of the level of theory has then been performed in order to obtain a computationally less demanding approach that is still able to reproduce the characteristic features of the reference data. Foreseeing the potentiality of 2D electronic spectroscopy to track polynucleotide ground and excited state dynamics, and in particular its expected ability to provide conformational dependent fingerprints in dimeric systems, the performances of the selected reduced level of calculations have been tested in the construction of 2D electronic spectra for the in vacuo adenine monomer and the unstacked adenine homodimer, thereby exciting the L b /L a transitions with the pump pulse pair and probing in the Vis to near ultraviolet spectral window. C 2015 AIP Publishing LLC. [http://dx

show abstract

Applications of level shift corrected perturbation theory in electronic spectroscopy

Cited by 188 publications

References 20 publications

Theoretical Modeling of Low‐Energy Electronic Absorption Bands in Reduced Cobaloximes

Theoretical Modeling of Low‐Energy Electronic Absorption Bands in Reduced Cobaloximes

Combining Internally Contracted States and Matrix Product States To Perform Multireference Perturbation Theory

Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy

Contact Info

Product

Resources

About