The ACES II program system

Stanton, John F.; Gauß, Jürgen; Watts, John D. W.; Lauderdale, Walter J.; Bartlett, Rodney J.

doi:10.1002/qua.560440876

Cited by 662 publications

(505 citation statements)

References 43 publications

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“…The doublet excited states have been obtained with the spin-restricted version of the open-shell equation-ofmotion coupled cluster method limited to singly-and doubly-excited configurations(EOM-CCSD) [65,66] implemented in the CFOUR package [67]. This approach allows for calculating excitation energies from the electronic ground state to the excited state of any spatial symmetry, but it is unable to calculate the spin-flip transitions (and thus those involving the quartet states).…”

Section: Methodsmentioning

confidence: 99%

Ground- and excited-state properties of the polar and paramagnetic RbSr molecule: A comparative study

2014

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This paper deals with the electronic structure of RbSr, a molecule possessing both a permanent magnetic and electric dipole moment in its own frame allowing its manipulation with external fields. Two complementary ab-initio approaches are used for the ground and lowest excited states: first, an approach relying on optimized effective core potentials with core polarization potentials based on a full configuration interaction involving three valence electrons, and second, an approach using a small-size effective core potential with 19 correlated electrons in the framework of coupled-cluster theory. We have found excellent agreement between these two approaches for the ground state properties including the permanent dipole moment. We have focused on studies of excited states correlated to the two lowest asymptotes Rb(5p 2 P )+Sr(5s 2 1 S) and Rb(5s 2 S)+Sr(5s5p 3 P ) relevant for ongoing experiments on quantum degenerate gases. We present also the Hund c) case potential curves obtained using atomic spin-orbit constants. These potential curves are an excellent starting point for experimental studies of molecular structure of RbSr using high-resolution spectroscopy.

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Section: Methodsmentioning

confidence: 99%

Ground- and excited-state properties of the polar and paramagnetic RbSr molecule: A comparative study

2014

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“…40,54 The calculations have been performed over a grid containing 364 points and employed the program package ACES II. 51 Since ACES II always reorients the molecular frame and performs the electronic structure calculations in the principal axes frame, special attention was paid for structures of C s point-group symmetry to reorient the core dipole corrections in order to make them consistent with the valence-only ones of MOLPRO. A file listing the 364 structures and the corresponding core corrections to the dipole moment components are given in EPAPS.…”

Section: B Core Correctionsmentioning

confidence: 99%

A new ab initio ground-state dipole moment surface for the water molecule

Lodi

Tolchenov

Tennyson

et al. 2008

The Journal of Chemical Physics

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A valence-only ͑V͒ dipole moment surface ͑DMS͒ has been computed for water at the internally contracted multireference configuration interaction level using the extended atom-centered correlation-consistent Gaussian basis set aug-cc-pV6Z. Small corrections to these dipole values, resulting from core correlation ͑C͒ and relativistic ͑R͒ effects, have also been computed and added to the V surface. The resulting DMS surface is hence called CVR. Interestingly, the C and R corrections cancel out each other almost completely over the whole grid of points investigated. The ground-state CVR dipole of H 2 16 O is 1.8676 D. This value compares well with the best ab initio one determined in this study, 1.8539Ϯ 0.0013 D, which in turn agrees well with the measured ground-state dipole moment of water, 1.8546͑6͒ D. Line intensities computed with the help of the CVR DMS shows that the present DMS is highly similar to though slightly more accurate than the best previous DMS of water determined by Schwenke and Partridge ͓J. Chem. Phys. 113, 16 ͑2000͔͒. The influence of the precision of the rovibrational wave functions computed using different potential energy surfaces ͑PESs͒ has been investigated and proved to be small, due mostly to the small discrepancies between the best ab initio and empirical PESs of water. Several different measures to test the DMS of water are advanced. The seemingly most sensitive measure is the comparison between the ab initio line intensities and those measured by ultralong pathlength methods which are sensitive to very weak transitions.

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“…Free GTO codes include the linear-scaling codes Ergo, [34,35] FreeON, [36] and CP2K, [37,38] and the orbital-based ACES II [39,40] and ACES III, [40,41] MPQC, [42] NWChem, [5,6] and PSI3 [43,44] codes. These programs constantly provide the usual functionalities related to energetics and static response functions, but often it is difficult to find software for more specific calculations, for example, for various spectroscopic applications.…”

Section: Introductionmentioning

confidence: 99%

ERKALE—A flexible program package for X‐ray properties of atoms and molecules

et al. 2012

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ERKALE is a novel software program for computing X-ray properties, such as ground-state electron momentum densities, Compton profiles, and core and valence electron excitation spectra of atoms and molecules. The program operates at Hartree-Fock or density-functional level of theory and supports Gaussian basis sets of arbitrary angular momentum and a wide variety of exchange-correlation functionals. ERKALE includes modern convergence accelerators such as Broyden and ADIIS and it is suitable for general use, as calculations with thousands of basis functions can routinely be performed on desktop computers. Furthermore, ERKALE is written in an object oriented manner, making the code easy to understand and to extend to new properties while being ideal also for teaching purposes.

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The ACES II program system

Cited by 662 publications

References 43 publications

Ground- and excited-state properties of the polar and paramagnetic RbSr molecule: A comparative study

Ground- and excited-state properties of the polar and paramagnetic RbSr molecule: A comparative study

A new ab initio ground-state dipole moment surface for the water molecule

ERKALE—A flexible program package for X‐ray properties of atoms and molecules

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