An Extended Jahn-Teller Hamiltonian for Large-Amplitude Motion: Application To Vibrational Conical Intersections in CH3SH and CH3OH

An extended Jahn-Teller Hamiltonian is presented for the case where the (slow) nuclear motion extends far from the symmetry point and may be described approximately as motion on a sphere. Rather than the traditional power series expansion in the displacement from the C3v symmetry point, an expansion in the spherical harmonics is employed. Application is made to the vibrational Jahn-Teller effect in CH3XH, with X = S, O, where the equilibrium CXH angles are 83° and 72°, respectively. In addition to the symmetry-required conical intersection (CI) at the C3v symmetry point, ab initio calculations reveal sets of six symmetry-allowed vibrational CIs in each molecule. The CIs for each molecule are arranged differently in the large-amplitude space, and that difference is reflected in the infrared spectra. The CIs in CH3SH are found in both eclipsed and staggered geometries, whereas those for CH3OH are found only in the eclipsed geometry near the torsional saddle point. This difference between the two molecules is reflected in the respective high-resolution spectra in the CH stretch fundamental region

Variation of CH stretch frequencies with CH4 orientation in the CH4 − F− complex: multiple resonances as vibrational conical intersections

In the \chem{CH_4 - F^-} complex, an adiabatic separation of the CH stretch frequencies from the \chem{CH_4} orientational coordinates allows the calculation of the four adiabatic CH stretch surfaces. These ab initio calculations reveal (i) a large variation of CH stretch frequencies (\textgreater 100 \wn) in the orientational space and (ii) the existence of four symmetrically equivalent sets of vibrational conical intersections (CIs). Two sets of symmetry-allowed CIs are identified in addition to the symmetry-required CIs at the front- and back-side C$_{3v}$ geometries. These results have implications for the evolution of excited CH vibrations in methane during its approach to a potentially reactive surface

VIBRATIONAL JAHN-TELLER EFFECT IN NON-DEGENERATE ELECTRONIC STATES

The Jahn-Teller theorem footnote{H.~A.~ Jahn, and E.~Teller, textit{Proc.~R.~Soc.~Lond.~A.} underline{textbf{161}},~220, (1937).} states that �All non-linear nuclear configurations are therefore unstable for an orbitally degenerate electronic state.� In 1982, Kellman footnote{M.~E.~ Kellman, textit{Chem.~Phys.~Lett.} underline{textbf{87}},~171, (1982).} realized that the Jahn-Teller theorem also applies to nonlinear molecular species in non-degenerate electronic states when there are high-frequency vibrations that are degenerate at a symmetrical reference geometry. When those high frequencies can be considered as adiabatic functions of degenerate low-frequency coordinates, there is a spontaneous Jahn-Teller distortion that lifts the degeneracy of the high-frequency vibrations. Kellman applied the vibrational Jahn-Teller (vJT) concept to the Van der Waals dimer (SF$_{6}$)$_{2}$. In this talk, the vJT concept is applied to E $otimes$ e systems that are small bound molecules in non-degenerate electronic states. The first case considered in systems for which the global minimum of the electronic potential has C$_{3v}$ symmetry.For such systems, including (C$_{6}$H$_{6}$)Cr(CO)$_{3}$ and CH$_{3}$CN, the vJT effect leads to a significant splitting of the degenerate high-frequency vibrations (CH or CO stretches), but the spontaneous vJT distortion is exceptionally small. The second case in systems for which the global minimum of the electronic potential is substantially distorted from the C$_{3v}$ reference geometry. For the second case systems, including CH$_{3}$OH and CH$_{3}$SH, the vJT splitting of the degenerate CH stretches is much larger, on the order of several 10ﾀﾙs of cm$^{-1}$). For both cases, there is the symmetry-required vibrational conical intersection at the C$_{3v}$ reference geometry. For the second case systems, there are additional symmetry-allowed vibrational conical intersections far from the C$_{3v}$ geometry but energetically accessible to the molecule at thermal energies. For both cases, the vibrationally adiabatic surfaces, including the multiple conical intersections, are well described by modest extensions to a high-order Hamiltonian that was developed for the electronic Jahn-Teller problem.footnote{A.~ Viel, and W.~Eisfeld, textit{J.~Chem.~Phys.} underline{textbf{120}},~4603, (2004).

An update on inflammatory breast cancer

Inflammatory breast cancer is one of the most aggressive forms of breast cancer. Once considered to be a uniformly fatal disease, treatment of this entity has evolved significantly over the last two decades. In this article, we review the epidemiology, pathology, biologic underpinnings, radiologic advances, and treatment modalities for inflammatory breast cancer. Updates in surgical therapy, medical oncologic therapy and radiation therapy are reviewed. Emphasis is on cutting edge information regarding inflammatory breast cancer. The management of inflammatory breast cancer is best served by a multidisciplinary team. Continued research into molecular pathways and potential targets is imperative. Future clinical trials should include evaluation of conventional therapy with targeted therapies