CHARACTERIZATION OF THE 1 5Πu - 1 5Πg BAND OF C2 BY TWO-COLOR RESONANT FOUR-WAVE MIXING AND LIF

Radi, Peter

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https://hdl.handle.net/2142/79306 Copy

Description

Title

CHARACTERIZATION OF THE 1 5Πu - 1 5Πg BAND OF C2 BY TWO-COLOR RESONANT FOUR-WAVE MIXING AND LIF

Author(s)

Radi, Peter

Issue Date

26-Jun-15

Keyword(s)

Electronic structure, potential energy surfaces

Abstract

newcommand{cdimb}{ensuremath{text{b};^3Sigma_text{g}^-}} newcommand{cdimd}{ensuremath{text{d};^3Pi_text{g}}} newcommand{cdimQlo}{ensuremath{text{1};^5Pi_text{g}}} newcommand{cdimQup}{ensuremath{text{1};^5Pi_text{u}}} The application of two-color resonant four-wave mixing (TC-RFWM) in combination with a discharge slit-source in a molecular beam environment is advantageous for the study of perturbations in C$_2$. Initial investigations have shown the potential of the method by a detailed deperturbation of the cdimd, $v=4$ state.footnote{P. Bornhauser, G. Knopp, T. Gerber, and P.P. Radi, Journal of Molecular Spectroscopy 262, 69 (2010)} The deperturbation of the cdimd, $v=6$ state unveiled the presence of the energetically lowest high-spin state of C$_2$. This dark state gains transition strength through the perturbation process with the cdimd, $v=6$ state yielding weak spectral features that are observable by the high sensitivity of the TC-RFWM technique. The successful deperturbation study of the cdimd, $v=6$ state resulted in the spectroscopic characterization of the quintet (cdimQlo) and an additional triplet state (cdimb, $v=19$). footnote{P. Bornhauser, Y. Sych, G. Knopp, T. Gerber, and P.P. Radi, Journal of Chemical Physics 134, 044302 (2011)} More recently, investigations have been performed by applying unfolded TC-RFWM to obtain further information on the quintet manifold. The first high-spin transition (cdimQup - cdimQlo) has been observed textit{via} an intermediate ``gateway'' state exhibiting both substantial triplet and quintet character owing to the perturbation between the cdimQlo, $v=0$ and the cdimd, $v=6$ states. The high-lying quintet state is found to be predissociative and displays a shallow potential that accommodates three vibrational levels only. footnote{Bornhauser, P., Marquardt, R., Gourlaouen, C., Knopp, G., Beck, M., Gerber, T., van Bokhoven, JA, and Radi, P. P., Journal of Physical Chemistry, submitted} Further studies of the high-spin system will be presented in this contribution. By applying TC-RFWM and laser-induced fluorescence, data on the vibrational structure of the cdimQup - cdimQlo , system is obtained. The results are combined with high-level ab initio computations at the multi-reference configuration interaction (MRCI) level of theory and the largest possible basis currently implemented in the 2012 version of MOLPRO.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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http://hdl.handle.net/2142/79306

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