Ab initio multi-reference perturbation theory calculations of the ground and low-lying electronic states of the KRb molecule

Shundalau, M. B.; Pitsevich, G. А.; Malevich, A. E.; Hlinisty, A.V.; Min'ko, A. A.; Ferber, R.; Tamanis, M.

doi:10.1016/j.comptc.2016.04.029

Cited by 16 publications

(11 citation statements)

References 52 publications

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“…The first three excited configurations, atomic states, and their energies of the Rb atom are: 5p ? 2 P 1/2 (12,578.950 cm À1 ), 2 (20,132.510 cm À1 ) [15]. The SOC splittings of the 2 P and 2 D terms are 237.595 and 0.446 cm À1 , respectively.…”

Section: Computationsmentioning

confidence: 99%

“…So, the following parameters of the ab initio calculations at the MRPT + SOC level of theory influence the calculation accuracy: a number of the states considered in the perturbation theory method [12] (i); qualitative composition (R, P, D) of the above-mentioned states [12] (ii); the energy denominator shift (EDS) for the intruder state avoidance (ISA) [12,18] (iii), and Z eff values [21] (iv). These parameters allow one to vary the energies of the low-lying atomic states, and the optimal choice of these parameters provides the required accuracy for the characteristics of the low-lying electronic molecular states.…”

Section: Computationsmentioning

confidence: 99%

“…Recently [11,12] we have shown that the ab initio calculations at the CASSCF/XMCQDPT2 (Extended Multi-Configuration Quasi-Degenerate 2nd Order Perturbation Theory) [13] level of theory predict the spectroscopic parameters of the ground state for the KRb molecule with a high accuracy. For the dissociation energy D e of the ground X 1 R + state, we have 4213.1 cm À1 that is in a better agreement with the experimental value (4217.815 cm À1 [14]) than those in other ab initio calculations (for details see [12]). The calculated equilibrium internuclear distance of the KRb ground X 1 R + state (R e = 4.07581 Å) also agrees considerably well with the experimental data by Pashov et al [14] (R e = 4.06770 Å).…”

Section: Introductionmentioning

confidence: 99%

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Ab initio multi-reference perturbation theory calculations of the ground and some excited electronic states of the RbYb molecule

Shundalau

Min'ko

2017

Computational and Theoretical Chemistry

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The potential energy curves of the ground and twelve low-lying excited electronic states of the RbYb molecule have been calculated using the multi-reference perturbation theory method at the CASSCF/ XMCQDPT2 level of theory including the spin-orbit coupling. The electronic term energies, equilibrium internuclear distances, dissociation energies, transition dipole moments, the sequences of vibrational energies, the harmonic vibrational frequencies, and the Franck-Condon factors have been predicted. The potential energy curves at the asymptotic limits are in a good agreement with the experimental data for rubidium and ytterbium atoms. The obtained data would be useful for spectral experiments with RbYb molecules.

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Section: Computationsmentioning

confidence: 99%

Section: Computationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ab initio multi-reference perturbation theory calculations of the ground and some excited electronic states of the RbYb molecule

Shundalau

Min'ko

2017

Computational and Theoretical Chemistry

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“…31 A new approach to the MS-MR-PT (Multi-State Multi-Reference Perturbation Theory) level of theory, which is called XMCQDPT (Extended Multi-Configuration Quasi-Degenerate Perturbation Theory), which is free from some disadvantages of the earlier versions of the MS-MR-PT, has been developed by Granovsky. 32 Recently, 33 we have shown that the ab initio calculations at the CASSCF/XMCQDPT2 (Extended Multi-Configuration Quasi-Degenerate 2 nd Order Perturbation Theory) 32 level of theory predict the spectroscopic parameters of the ground and some excited states of the KRb molecule with the high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Structure of N′-(adamantan-2-ylidene)benzohydrazide, a potential antibacterial agent, in solution: Molecular dynamics simulations, quantum chemical calculations and Ultraviolet–visible spectroscopy studies

et al. 2016

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The molecular dynamics simulations of the structure of the N-(adamantan-2-ylidene)benzohydrazide followed by the quantum chemical calculations at the DFT level of theory have identified four stable conformers of this potential antibacterial agent in solution: one "central" cis-and three ("central", "left" and "right") trans-conformers. The UV-Vis absorption spectrum in the 220-320 nm region in the ethanol solution reveals two bands that can be primarily explained based on the ab initio calculations of the spectral characteristics of the "side" trans-conformers at the MRPT level of theory. However, the close energy values for the calculated cis-S 1 ← S 0 and "side" trans-S 2 ← S 0 transitions cannot exclude the presence of cis-conformer in solution. Therefore, the data obtained show that the coexistence of both trans-conformers and cis-conformer should be taken into consideration when studying the pharmaceutical properties of the title molecule.

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“…The comprehensive set of non-relativistic PECs, permanent and transition dipole moments for the ground and excited states of KRb are available 11,[21][22][23][24][25] as well. The SOC effect has been included into ab initio calculations in Refs.…”

Section: Introductionmentioning

confidence: 99%

Twofold diabatization of the KRb(1–2)Π1complex in the framework ofab initioand deperturbation approaches

2016

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The twofold diabatization of the KRb (1 ∼ 2) We performed a diabatization of the mutually perturbed 1 1 Π and 2 1 Π states of KRb based on both electronic structure calculation and direct coupled-channel deperturbation analysis of experimental energies. The potential energy curves (PECs) of the diabatic states and their scalar coupling were constructed from the ab initio adiabatic PECs by analytically integrating the radial ψ ad 1 |∂/∂R|ψ ad 2 matrix element obtained by a finite-difference method. The diabatic potentials and electronic coupling function were refined by the least squares fitting of the rovibronic termvalues of the 1 1 Π ∼ 2 1 Π complex. The empirical PECs combined with the coupling function as well as the diabatized spin-orbit coupling and transition dipole matrix elements are useful for further deperturbation treatment of both singlet and triplet states manifold. I. INTRODUCTIONThe accurate representation of the interacting electronic states plays a key role in understanding the detailed mechanism of the photo and collisionally induced chemical reactions. The singlet-triplet levels of alkali metal dimers serve as an intermediate state in the two step optical transformation of the weakly bound atomic pairs into the absolute ground X 1 Σ + (v = 0, J = 0) molecular state 1,2 . To suppress the undesired spontaneous transitions to the low-lying states a coherent stimulated Raman adiabatic passage 3 (STIRAP) is often used.The photoassociative production and trapping of ultracold KRb molecules has been performed 4 . The resonance coupling of the B(1) 1 Π and 2 1 Π states of KRb (see, Fig. 1) is found to be a promising pathway for direct photoassociative formation of the X(0, 0) ultracold molecules 5 . The rigorous multi-channel modeling of the laser formation of vibrationally cold KRb molecules has been accomplished in Ref. 6 9,10 to the lowest X(0, 0) level through the B 1 Π ∼ c 3 Σ + levels located near the second dissociation threshold.A comprehensive review of modern spectroscopic studies of the KRb electronic states can be found in the ebook 12 . The mutually perturbed 1 1 Π and 2 1 Π states converging to the second K(4 2 S)+Rb(5 2 P) and third K(4 2 P)+Rb(5 2 S) dissociation thresholds were investigated 13,14 using Doppler-free optical-optical double resonance polarization spectroscopy (OODRPS). In the sub- 15,16 included in the present CC deperturbation analysis. The inset enlarges the region in the vicinity of the crossing point of V1(R) and V2(R) diabatic PECs.The adiabatic potentials, permanent and transition dipole moments for the radially coupled 1 1 Π and 2 1 Π states were first ab initio calculated in Refs 19 and 20. The comprehensive set of non-relativistic PECs, permanent and transition dipole moments for the ground and excited states of KRb are available 11,21-25 as well. The SOC effect has been included into ab initio calculations in Refs. 6,11,24,and 26. Among other alkali diatomics, the KRb molecule stands out because of the high density of the electronic states belonging to both...

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Ab initio multi-reference perturbation theory calculations of the ground and low-lying electronic states of the KRb molecule

Cited by 16 publications

References 52 publications

Ab initio multi-reference perturbation theory calculations of the ground and some excited electronic states of the RbYb molecule

Ab initio multi-reference perturbation theory calculations of the ground and some excited electronic states of the RbYb molecule

Structure of N′-(adamantan-2-ylidene)benzohydrazide, a potential antibacterial agent, in solution: Molecular dynamics simulations, quantum chemical calculations and Ultraviolet–visible spectroscopy studies

Twofold diabatization of the KRb(1–2)Π1complex in the framework ofab initioand deperturbation approaches

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