The Molpro quantum chemistry package

Werner, Hans‐Joachim; Knowles, Peter J.; Manby, Frederick R.; Black, Joshua A.; Doll, K.; Heßelmann, Andreas; Kats, Daniel; Köhn, Andreas; Korona, Tatiana; Kreplin, David A.; Ma, Qianli; Miller, Thomas F.; Mitrushchenkov, Alexander; Peterson, Kirk A.; Polyak, Iakov; Rauhut, Guntram; Sibaev, Marat

doi:10.1063/5.0005081

Cited by 803 publications

(761 citation statements)

References 367 publications

(431 reference statements)

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“…is the starting point of the dissociation region, and −iW is the CAP. To calculate the potential energy, the dipole moment, and the NAC curves of the LiF molecule ( figure 1(b)), the program packages Molpro [55] was used. These quantities were calculated at the MRCI/CAS(6/12)/aug-cc-pVQZ level of theory [56].…”

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confidence: 99%

Ultrafast dynamics in the vicinity of quantum light-induced conical intersections

et al. 2019

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Nonadiabatic effects appear due to avoided crossings or conical intersections (CIs) that are either intrinsic properties in field-free space or induced by a classical laser field in a molecule. It was demonstrated that avoided crossings in diatomics can also be created in an optical cavity. Here, the quantized radiation field mixes the nuclear and electronic degrees of freedom creating hybrid fieldmatter states called polaritons. In the present theoretical study we go further and create CIs in diatomics by means of a radiation field in the framework of cavity quantum electrodynamics. By treating all degrees of freedom, that is the rotational, vibrational, electronic and photonic degrees of freedom on an equal footing we can control the nonadiabatic quantum light-induced dynamics by means of CIs. First, the pronounced difference between the the quantum light-induced avoided crossing and the CI with respect to the nonadiabatic dynamics of the molecule is demonstrated. Second, we discuss the similarities and differences between the classical and the quantum field description of the light for the studied scenario.The dynamics initiated in a molecule by absorbing a photon is often described in the Born-Oppenheimer (BO) or adiabatic approximation [1], where the electronic and nuclear degrees of freedom are treated separately. However, in some nuclear configurations called conical intersections (CIs) the mixing between the electronic and nuclear motions are very significant [2][3][4][5][6]. Owing to the strong nonadiabatic couplings (NACs) in the close vicinity of these CIs the BO approximation breaks down. It is well-known that these CIs have a significant impact on several important photo-dynamical processes, such as vision, photosynthesis, molecular electronics, and the photochemistry of DNA [7][8][9][10][11]. During the dynamics the CIs can serve as efficient decay channels for the ultrafast transfer of the populations. In the following we call these CIs, which originate from the field free electronic structure, natural CIs.Nonadiabatic effects can also appear when molecules are exposed to resonant laser light. The electric field can couple to two or more electronic states of the molecule via the non-vanishing transition dipole moment(s) [12][13][14][15]. This results either in a light-induced avoided crossing (LIAC) or a light-induced conical intersection (LICI) depending on how many nuclear degrees of freedom are involved in the field induced process [16]. In case of poly atomic molecules a sufficient number of vibrational degrees of freedom are always present to span a twodimensional branching space (BS), which is indispensable to the formation of LICI. In the case of diatomics one always has to find a proper second degree of freedom (DOF) which can act as a dynamical variable to form a BS. As the molecule rotates [17][18][19], the rotational angle between the molecular axis and the light polarization axis can serve as the missing DOF for establishing the BS [20].Nonadiabatic effects can arise in an optical or mi...

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confidence: 99%

Ultrafast dynamics in the vicinity of quantum light-induced conical intersections

et al. 2019

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“…The use of such large basis sets is well known to recover 98% of the electron correlation effects in molecular structure calculations (Helgaker et al 2000). All the PEC and TDM calculations for the C 2 molecule were performed with the quantum chemistry program package molpro 2015.1 (Werner et al 2015), running on parallel architectures.…”

Section: Potential Curves and Transition Dipole Momentsmentioning

confidence: 99%

“…In order to take account of short-range interactions, we employed the non-relativistic state-averaged complete active-space-self-consistent-field (SA-CASSCF)/MRCI method available within the molpro (Werner et al 2012(Werner et al , 2015 quantum chemistry suite of codes.…”

Section: Potential Curves and Transition Dipole Momentsmentioning

confidence: 99%

Dicarbon Formation in Collisions of Two Carbon Atoms

Babb¹,

Smyth

McLaughlin

2019

ApJ

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Radiative association cross sections and rates are computed, using a quantum approach, for the formation of C 2 molecules (dicarbon) during the collision of two ground state C( 3 P) atoms. We find that transitions originating in the C 1 Π g , d 3 Π g , and 1 5 Π u states are the main contributors to the process. The results are compared and contrasted with previous results obtained from a semi-classical approximation. New ab initio potential curves and transition dipole moment functions have been obtained for the present work using the multi-reference configuration interaction approach with the Davidson correction (MRCI+Q) and aug-cc-pCV5Z basis sets, substantially increasing the available molecular data on dicarbon. Applications of the current computations to various astrophysical environments and laboratory studies are briefly discussed focusing on these rates.1 CO was also detected in the first overtone band (∆ν = 2). In SN 1987A individual rotational lines of CO and of SiO were detected at late epoch, see Abellán et al. (2017);Sarangi et al. (2018).

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“…The molecule is assumed to be pre-oriented, e.g., by the nonadiabatic optical alignment technique [68,69]. We executed ab initio electronic structure calculations for DCP with the 6-31G* Gaussian basis set [70] by using the quantum chemistry program MOLPRO [71]. The geometry of DCP was optimized in the ground state at the level of the second-order Møller-Plesset perturbation theory (MP2) [72] and the optimized geometry was of C 2h symmetry.…”

Section: Numerical Demonstration For 25-dichloropyrazinementioning

confidence: 99%

Laser-Control of Ultrafast π-Electron Ring Currents in Aromatic Molecules: Roles of Molecular Symmetry and Light Polarization

2018

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Being motivated by the recent progress in attosecond laser technology, we theoretically explore the strategy of inducing ultrafast electron dynamics inherent to aromatic molecules, i.e., ring currents by means of polarized laser pulses. The main topic of discussion is how to control the direction of ring currents in an aromatic molecule of low symmetry, for which the design of an efficient control pulse cannot be achieved intuitively. We first consider a system with a single aromatic ring and show that coherent π-electron angular momentum, which oscillates with time, can be produced and controlled by a polarized laser pulse with its ellipticity and orientation properly chosen. Nonadiabatic couplings with molecular vibration gradually weaken the angular momentum, while the vibrational amplitude strongly depends on the polarization of incident light. This suggests the conversion of the polarization dependence of ring current into that of subsequent vibration, which may open a way to detect laser-driven ultrafast electron dynamics by vibrational spectroscopy. The laser-control scheme for the ring current is then extended to a molecule with two aromatic rings, which exhibits characteristic phenomena absent in that with a single ring. We demonstrate that two-dimensional switching of the direction of angular momentum is possible in such molecules. In addition, ring current can be localized at a specific ring by tailored lasers. The application of the present control method to polycyclic aromatic hydrocarbons will lead to the development of next-generation organic optical switching devices.

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The Molpro quantum chemistry package

Cited by 803 publications

References 367 publications

Ultrafast dynamics in the vicinity of quantum light-induced conical intersections

Ultrafast dynamics in the vicinity of quantum light-induced conical intersections

Dicarbon Formation in Collisions of Two Carbon Atoms

Laser-Control of Ultrafast π-Electron Ring Currents in Aromatic Molecules: Roles of Molecular Symmetry and Light Polarization

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