Anharmonic spectra of methanol and silanol: A comparative study

Ureña, Francisco Partal; González, Juan Jesús López; Márquez, Fernando José

doi:10.1016/j.jms.2005.07.001

Cited by 7 publications

(5 citation statements)

References 56 publications

(109 reference statements)

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“…The computational assessment shown in Table 1 comprises an extensive statistical analysis of the accuracy of five different PES setups in our calculations. Additionally, we compare our results to a variety of previous calculations regarding the fundamental vibrational frequencies [60][61][62][63][64]. Details of the PES setups (S1-S5) are listed together with the results.…”

Section: Computational Assessment On the Example Of Methanolmentioning

confidence: 88%

“…To demonstrate the performance of the VSCF/VCI approach when using different setups in the construction of the PES, we first provide a computational assessment. At the example of methanol, we compare our computational results to our experimental MI-IR data as well as the literature data from the experiment [28,[56][57][58][59] and other computational approaches [60][61][62][63][64]. Apart from this assessment, we present results from VSCF/VCI calculations as a support in the conceptualization of MI-IR spectra.…”

Section: Introductionmentioning

confidence: 86%

“…Furthermore, using coupled-cluster theory in the computation of the electronic structure provides the most accurate PES. Given an accurate PES with up to 4D potentials, the VSCF/VCI calculations presented here are as functional as previous calculations (MM-RPH [63], VPT2 [60], and VV/VC [61]), or even better (fast-VSCF/VCI [64], cc-VSCF [62]). This comparison must be, however, appreciated with care.…”

Section: Findings From the Computational Assessmentmentioning

confidence: 99%

“…details in Ref. [62] m Perturbative/variational approach relying on anharmonic quartic force-field at CCSD(T)/cc-pVTZ level of theory, cf. details in Ref.…”

Section: Computational Assessment On the Example Of Methanolmentioning

confidence: 99%

“…In the past, a variety of computational approaches have been studied regarding the fundamental vibrations of the methanol molecule. We consider three studies using variational approaches (fast-VSCF/VCI [64], MM-RPH [63], cc-VSCF [62]) that are in parts similar to the approach in this work. Furthermore, we mention one study using a perturbative approach (VPT2 [60]) and another using a mixture of perturbative and variational approaches (VV/VC [61]).…”

Section: Fundamental Vibrational Frequenciesmentioning

confidence: 99%

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On the synergy of matrix-isolation infrared spectroscopy and vibrational configuration interaction computations

et al. 2020

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The key feature of matrix-isolation infrared (MI-IR) spectroscopy is the isolation of single guest molecules in a host system at cryogenic conditions. The matrix mostly hinders rotation of the guest molecule, providing access to pure vibrational features. Vibrational self-consistent field (VSCF) and configuration interaction computations (VCI) on ab initio multimode potential energy surfaces (PES) give rise to anharmonic vibrational spectra. In a single-sourced combination of these experimental and computational approaches, we have established an iterative spectroscopic characterization procedure. The present article reviews the scope of this procedure by highlighting the strengths and limitations based on the examples of water, carbon dioxide, methane, methanol, and fluoroethane. An assessment of setups for the construction of the multimode PES on the example of methanol demonstrates that CCSD(T)-F12 level of theory is preferable to compute (a) accurate vibrational frequencies and (b) equilibrium or vibrationally averaged structural parameters. Our procedure has allowed us to uniquely assign unknown or disputed bands and enabled us to clarify problematic spectral regions that are crowded with combination bands and overtones. Besides spectroscopic assignment, the excellent agreement between theory and experiment paves the way to tackle questions of rather fundamental nature as to whether or not matrix effects are systematic, and it shows the limits of conventional notations used by spectroscopists.

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Section: Computational Assessment On the Example Of Methanolmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 86%

Section: Findings From the Computational Assessmentmentioning

confidence: 99%

“…details in Ref. [62] m Perturbative/variational approach relying on anharmonic quartic force-field at CCSD(T)/cc-pVTZ level of theory, cf. details in Ref.…”

Section: Computational Assessment On the Example Of Methanolmentioning

confidence: 99%