# Browse Abstracts & Presentations - 2014 International Symposium on Molecular Spectroscopy by Subject "Theory and Computation"

• (International Symposium on Molecular Spectroscopy, 2014-06-20)
The C$_3$Ar and C$_3$Ne complexes have four large amplitude vibrations. These are the in- and out-of-plane C$_3$ bending motions, and the two van der Waals vibrations. Assignment of the spectra of the complexes is therefore ...

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Microsoft PowerPoint 2007 (2MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
Accurate structures of aminoacids in the gas phase have been obtained by joint microwave and quantum-chemical investigations. However, the structure and conformational behavior of $\alpha$-aminoacids once incorporated into ...

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Microsoft PowerPoint 2007 (19MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
Computational spectroscopy techniques have become in the last years effective means to predict and characterize spectra, such as infrared, for molecular systems of increasing dimensions with account for different environments. ...

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Microsoft PowerPoint 2007 (5MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
Advances in hardware performance and the availability of efficient and reliable computational models have made possible the application of computational spectroscopy to ever larger molecular systems. The systematic ...

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Microsoft PowerPoint 2007 (632kB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
Fourth-Order Rayleigh-Schrodinger Perturbation Theory (VPT4) is applied to a series of small molecules. The quality of results have been shown to be heavily dependent on the quality of the quintic and sextic force constants ...

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Microsoft PowerPoint 2007 (763kB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
The derivation of analytic expressions for vibrational and rovibrational constants, for example the anharmonicity constants $\chi_{ij}$ and the vibration-rotation interaction constants $\alpha^B_r$, from second-order ...

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PDF (4MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
We have carried out TDDFT computational studies on the low-lying excited states of di-{\it tert}-butylaminobenzonitrile and 2,4,6-tricyanoaniline compounds that exhibit unusual photophysical behaviors associated with the ...

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Microsoft PowerPoint 2007 (5MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
The discovery of a set of seven conical intersections (CI’s) between vibrationally adiabatic surfaces in methanol is reported. The intersecting surfaces represent the energies of the two asymmetric CH stretch vibrations, ...

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Microsoft PowerPoint 2007 (9MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
When disubstituted benzene molecules are considered the relative position of the substituents must be defined. The three possible forms are ortho-, meta-, and para- where the latter is investigated in this work by consideration ...

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Microsoft PowerPoint 2007 (9MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
Recently interest in polar diatomic molecules with a magnetic dipole moment has been growing. An example for such molecules is the combination of an alkali metal atom and an alkaline earth metal atom. These systems are ...

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Microsoft PowerPoint 2007 (6MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
The free O-H stretching modes of H$^{+}$(CH$_{3}$OH)$_{1-3}$ clusters with/without argon have been unraveled by combining Infrared Pre-Dissociation (IR-PD) spectra and multidimensional normal mode analysis by Density ...

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Microsoft PowerPoint 2007 (8MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
New potential energy surfaces for methane were constructed, represented as analytic fits to about 100,000 individual high-level ab initio data. Explicitly-correlated multireference data (MRCI-F12(AE)/CVQZ-F12) were computed ...

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Microsoft PowerPoint 2007 (7MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
Accurate quantum-chemical calculations of metal quadrupole-coupling parameters are challenging due to the sensitivity of these parameters to both relativistic and electron-correlation effects. In the present study we have ...

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Microsoft PowerPoint 2007 (1MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
The ubiquitous nature of the low-lying $\pi\sigma$* state in the photo-excited aromatic molecules or biomolecules is widely recognized to play an important role in nonadiabatic photo-process such as photodissociation or ...

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Microsoft PowerPoint 2007 (7MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
Large amplitude vibrations of Van der Waals clusters are important because they reveal large regions of a potential energy surface (PES). To calculate spectra of Van der Waals clusters it is common to use ...

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PDF (3MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
The structure of the purely rotational spectrum of sulphur trioxide $SO_3$ is investigated using a new synthetic line list. The list combines line positions from an empirical model with line intensities determined, in ...

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Microsoft PowerPoint 2007 (9MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
The nuclear Schr\"{o}dinger equation forms the basis for vibrational perturbation theory. However, the canonical $\hat{H}\Psi=E\Psi$" form is shown to be insufficient for computing elements of the rotational effective ...

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PDF (3MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
Two parallel theories including Franck–Condon, Herzberg–Teller and Duschinsky (i.e., mode mixing) effects, allowing different approximations for the description of excited state PES have been developed in order to simulate ...

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PDF (2MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-19)
In this work, an extension to diffusion Monte Carlo (DMC) is proposed, allowing for the simultaneous calculation of the energy and wave function of multiple rotationally excited states of floppy molecules.\footnote{A. S. ...

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Microsoft PowerPoint 2007 (4MB)
• (International Symposium on Molecular Spectroscopy, 2014-06-20)
The rich spectroscopy of the ethyl radical has attracted the attention of several experimental and theoretical investigations. Its molecular spectrum contains signatures of hyperconjugation, torsion-inversion coupling, and ...

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Microsoft PowerPoint 2007 (3MB)