Ab Initio Calculations of Thermochemical Properties of Methanol Clusters

Umer, Muhammad; Leonhard, Kai

doi:10.1021/jp308908j

Cited by 52 publications

(39 citation statements)

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“…In the oligomers, the possibility of different O···H-O-C3 dihedral orientations (figure 9) for the cyclic trimer and tetramer should be taken into account. Similar structures were previously computed for gas associates of methanol [64]. Linear forms of trimer and tetramer associates were found to be significantly less stable than the cyclic variants [64].…”

Section: Gas Phase Association and Its Effect On Thermodynamic Propersupporting

confidence: 76%

“…Similar structures were previously computed for gas associates of methanol [64]. Linear forms of trimer and tetramer associates were found to be significantly less stable than the cyclic variants [64]. The cyclic forms with alternating values of O···H-O-C3 dihedrals were found to be more stable relative to systems with equal values.…”

Section: Gas Phase Association and Its Effect On Thermodynamic Propersupporting

confidence: 72%

“…For methanol clusters, the stable tetramer forms were udud and uudd [64]. The presence of a bulky hydrocarbon substituent in 2-methyl-3-buten-2-ol distorted the plane of the O-H and the hydrogen bonds in such way that the hypothetical uuuu, uuud, and uudd orientations converted into udud.…”

Section: Gas Phase Association and Its Effect On Thermodynamic Propermentioning

confidence: 99%

See 2 more Smart Citations

Comprehensive study of the thermodynamic properties for 2-methyl-3-buten-2-ol

Zaitsau

Paulechka

Firaha

et al. 2015

The Journal of Chemical Thermodynamics

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Section: Gas Phase Association and Its Effect On Thermodynamic Propersupporting

confidence: 76%

Section: Gas Phase Association and Its Effect On Thermodynamic Propersupporting

confidence: 72%

See 1 more Smart Citation

Comprehensive study of the thermodynamic properties for 2-methyl-3-buten-2-ol

Zaitsau

Paulechka

Firaha

et al. 2015

The Journal of Chemical Thermodynamics

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“…39 Unfortunately, vibrational perturbation treatments to include such effects [40][41][42] are not always reliable over the entire spectrum of normal modes for floppy systems. 43 While they provide fairly reliable high frequency mode corrections, 36 they occasionally tend to predict unphysical anharmonicity effects for large amplitude low frequency modes. In the present case, imaginary anharmonic frequencies were persistent for the OH-O and OH-p 0 isomers.…”

Section: Towards Possible Explanationsmentioning

confidence: 99%

To π or not to π – how does methanol dock onto anisole?

Heger

Altnöder

Poblotzki

et al. 2015

Phys. Chem. Chem. Phys.

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Anisole offers two similarly attractive hydrogen bond acceptor sites to an incoming hydrogen bond donor: its oxygen atom and its delocalized π electron system. Electronic structure calculations up to the CCSD(T)/AVTZ level suggest an isoenergetic situation for methanol after harmonic zero point energy correction, within less than 1 kJ mol(-1). Linear infrared absorption spectroscopy in the OH stretching fundamental range applied to a cold supersonic jet expansion of anisole and methanol in helium shows that the oxygen binding site is preferred, with about 20 times less π-bonded than O-bonded dimers despite the non-equilibrium collisional environment. Accidental band overlap is ruled out by OH overtone and OD stretching spectroscopy. Furthermore, the diagonal anharmonicity constant of the OH stretching mode is derived from experiment and reaches 80% of the monomer distortion found in the methanol dimer, as expected for a weaker hydrogen bond to the aromatically substituted oxygen. To reconcile these experimental findings with ab initio theory, accurate nuclear and electronic structure calculations involving AVQZ basis sets are required. Dispersion-corrected double-hybrid density functional theory provides a less expensive successful structural approach.

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“…[4] Less stability of branched cyclic structures has been previously found in methanol clusters. [45][46][47][48][49][50][51] Generally, the relative stability of the structures of the ethanol hexamer reported in this work follow the same trend as that of the methanol clusters. Although branched cyclic structures are among the less stable structures, among all the investigated structures of the ethanol hexamer, the flat cyclic hexamer comprising six trans monomers is found to be the least stable (see Figure 3).…”

Section: Structures and Relative Probabilitiesmentioning

confidence: 73%

Theoretical infrared spectrum of the ethanol hexamer

Malloum

Fifen

Conradie

2020

Int J of Quantum Chemistry

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The hydrogen bond network of ethanol clusters is among the most complex hydrogen bond networks of molecular clusters. One of the reasons of its complexity arises from the number of possible ethanol monomers (there are three isoenergetic isomers of the ethanol monomer). This leads to difficulties in the exploration of potential energy surfaces (PESs) of ethanol clusters. In this work, we have explored the PES of the ethanol hexamer at the MP2/aug-cc-pVDZ level of theory. We have provided structures and their relative stability at 0 K and for temperatures ranging from 20 to 400 K in the gas phase. These structures are used to compute the theoretical infrared (IR) spectrum of the ethanol hexamer at the MP2/aug-cc-pVDZ level of theory. As a result, 98 different structures have been investigated, and six isomers are reported to be the most isoenergetically stable structures of the ethanol hexamer. These isomers are folded cyclic structures in which the stability is enhanced by the implication of CHÁ Á ÁO interactions. Our investigations show that the PES of the ethanol hexamer is very flat, yielding several isoenergetic structures. Furthermore, we have noted that several isomers contribute to the population of the ethanol hexamer at high temperatures. As far as the IR spectroscopic study is concerned, we have found that the IR spectra of the most stable structures are in good agreement with the experiment.Considering this agreement, these structures are used to assign the experimental peaks in the CH-stretching region. We concluded that the stability of the structures of the ethanol hexamer is related both to OHÁ Á ÁO hydrogen bonds and CHÁ Á ÁO interactions. Overall, we have found that the IR spectrum of the ethanol hexamer, calculated from the contribution of all the possible stable structures weighted by their probability, excellently reproduce the experimental spectrum of the ethanol hexamer. K E Y W O R D S ethanol clusters, ethanol hexamer, infrared spectrum, relative population, Voigt profile 1 | INTRODUCTIONLiquid ethanol has important applications in industries, and it is widely used as a solvent in chemical processes. Besides, ethanol has many applications in medicine and pharmacology. [1] Understanding of some properties of liquid ethanol is related to the hydrogen bond networks of ethanol clusters (EtOH) n . The hydrogen bond networks of the ethanol clusters are among the most complex hydrogen bond networks in molecular clusters. One of the reasons of this complexity is the high number of possible stable structures of the ethanol monomer (there are three isoenergetic isomers of the ethanol monomer: gauche−, trans, and gauche+ related to the value of the CCOH dihedral angles −60 , 180 , and +60 , respectively). [2][3][4] Most of the investigations performed on ethanol clusters are limited to the ethanol dimer due to difficulties arising from the exploration of the potential energy surfaces (PESs) of the ethanol clusters. [2,3,[5][6][7][8][9][10][11] Reliable investigations performed on the ethanol dimer,

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Ab Initio Calculations of Thermochemical Properties of Methanol Clusters

Cited by 52 publications

References 50 publications

Comprehensive study of the thermodynamic properties for 2-methyl-3-buten-2-ol

Comprehensive study of the thermodynamic properties for 2-methyl-3-buten-2-ol

To π or not to π – how does methanol dock onto anisole?

Theoretical infrared spectrum of the ethanol hexamer

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