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The Anharmonic Correction of Normal Mode Vibrations
Published in Mihai V. Putz, New Frontiers in Nanochemistry, 2020
Software modules dedicated to anharmonic frequency corrections are included in several quantum chemistry program packages: GAUSSIAN09 (www.gaussian.com), Molpro 2015.1 (https://www.molpro.net/), GAMESS (http://www.msg.ameslab.gov/ga-mess/), CFour (http://www.cfour.de/), or NWChem (http://www.nwchem-sw.org).
Globally accurate potential energy surface for PH2 + (11 A′) by using the switching function formalism
Published in Molecular Physics, 2020
Y. L. Lü, S. J. Chai, H. Y. Ma, S. B. Gao, Y. Q. Li
The quantum chemical software molpro focuses on high precision calculations, and is applicable to multi-electron systems. Based on molpro2012 [25], ab initio points were calculated by the MRCI(Q) [20,21] method with the FVCAS [22] wave function as reference. All 3041 ab initio points were calculated based on the correlation-consistent basis sets AVQZ of Dunning [17–19]. For the symmetrical configuration , ab initio energies were defined at , , and . The ab initio points in another asymmetric configuration, , were defined at , , and . Here, R, r, and γ represent variable quantities with Jacobi coordinates [26–28] for all dissociation channels. The whole ab initio calculation process consists of six active orbitals (5A ' + 1A") and a total of 176 (113A' + 63A") configuration state functions for the FVCAS of .
Accurate global adiabatic potential energy surface for the ground state of AlH2+ by extrapolation to the complete basis set limit
Published in Molecular Physics, 2020
S. J. Chai, H. Y. Ma, Y. L. Lü, J. Y. Liu, Y. Q. Li
The MOLPRO [20] software package is professional quantum chemical computing software, which calculated electronic structure with high accuracy. Here the molpro2012 version is employed to calculate the electronic state energies of in different configurations. The 2897 ab initio points in Jacobi coordinates were firstly acquired by MRCI(Q) [21,22] method with FVCAS [21] wave function as reference and combining with the Dunning consistent basis sets AV(Q, 5)Z [23]. Then, the energies were extrapolated to the CBS limit by employing USTE scheme [24]. Finally, the ab initio energies were fitted by the MBE scheme [25–27], which developed by Aguado and Paniagua [28,29] and had successfully applied in other triatomic systems, such as [30], and [31,32].