TY - JOUR

T1 - Toward Accurate Theoretical Vibrational Spectra: A Case Study for Maleimide

AU - Klinting, E.L.

AU - Christiansen, O.

AU - König, Carolin

N1 - Funding information: O.C. acknowledges support from the Danish e-infrastructure Cooperation (DeiC) and the Danish Council for Independent Research through a Sapere Aude III Grant (no. DFF-4002-00015). C.K. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG) through the Emmy Noether Young Group Leader Programme (project KO 5423/1-1).

PY - 2020/4/2

Y1 - 2020/4/2

N2 - We employ and combine a number of recent developments in vibrational structure methods to push their current size limitations toward molecules with tens of modes and showcase their availability for the maleimide molecule. In particular, we assess the use of different rectilinear vibrational coordinates, namely, normal coordinates, hybrid optimized and localized coordinates, and flexible adaptation of local coordinates of nuclei coordinates. These different coordinate parameterizations are employed in conjunction with the adaptive density-guided approach to generate potential energy surfaces (PESs). A screening procedure is furthermore introduced, which provides estimates of the importance of individual terms in the PES, resulting in significant reductions in the computational cost of the PES construction. We find that all three sets of coordinates provide approximately the same level of accuracy in vibrational structure calculations and report fundamental excitation energies with a mean absolute deviation of less than 12 cm -1 when compared to experimental data. We expect that similar accuracy in vibrational structure calculations can be achieved for molecules of larger size using the proposed procedures.

AB - We employ and combine a number of recent developments in vibrational structure methods to push their current size limitations toward molecules with tens of modes and showcase their availability for the maleimide molecule. In particular, we assess the use of different rectilinear vibrational coordinates, namely, normal coordinates, hybrid optimized and localized coordinates, and flexible adaptation of local coordinates of nuclei coordinates. These different coordinate parameterizations are employed in conjunction with the adaptive density-guided approach to generate potential energy surfaces (PESs). A screening procedure is furthermore introduced, which provides estimates of the importance of individual terms in the PES, resulting in significant reductions in the computational cost of the PES construction. We find that all three sets of coordinates provide approximately the same level of accuracy in vibrational structure calculations and report fundamental excitation energies with a mean absolute deviation of less than 12 cm -1 when compared to experimental data. We expect that similar accuracy in vibrational structure calculations can be achieved for molecules of larger size using the proposed procedures.

UR - http://www.scopus.com/inward/record.url?scp=85082979022&partnerID=8YFLogxK

U2 - 10.1021/acs.jpca.9b11915

DO - 10.1021/acs.jpca.9b11915

M3 - Article

VL - 124

SP - 2616

EP - 2627

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 13

ER -