The B2Π–X2Π electronic origin band of 13C6H

Abstract

a b s t r a c tThe rotationally resolved spectrum of the B 2 P-X 2 P electronic origin band transition of 13 C 6 H is presented. The spectrum is recorded using cavity ring-down spectroscopy in combination with supersonic plasma jets by discharging a 13 C 2 H 2 /He/Ar gas mixture. A detailed analysis of more than a hundred fully-resolved transitions allows for an accurate determination of the spectroscopic parameters for both the ground and electronically excited state of 13 C 6 H.

Spectroscopic Survey of Electronic Transitions of C6H, 13C6H, and C6D

“…Bands I and II: 0 0 0 B 2 Π Ω ´X2 Π Ω origin band Fully resolved rovibronic spectra of the B 2 Π´X 2 Π origin band transition have been reported before. 6,17,31 Figure 2 shows the cavity ring-down spectra of C 6 H, 13 C 6 H, and C 6 D. The spectra are repeated for completeness and as an introduction to the interpretation of the other 2 Π ´2Π bands presented later.…”

“…These findings apply with approximately the same values to all three species. The fitting of the observed spectra is rather straightforward as very precise microwave constants are available to characterize the electronic ground state, but only for the case of C 6 H and C 6 D. 6 Since there are no ground state constants for the 13 C 6 H species from microwave or infrared spectroscopy, both the upper and the lower energy levels of the B 2 Π´X 2 Π (0,0) transition are optimized in the fitting, 31 and the resulting ground state molecular constants will be used for the simulation and fitting of the other 13 C 6 H bands.…”

“…In previous work, extensive lists with line positions have been given for these bands and using accurate molecular parameters have been derived for C 6 H and C 6 D, as well as for the 13 C-substituted species . The molecular constants are collected in Table .…”

“…In previous work, extensive lists with line positions have been given for these bands and using PGOPHER accurate molecular parameters have been derived for C 6 H and C 6 D, 17 as well as for the 13 C-substituted species. 31 The molecular constants are collected in Table 1. Shown in Figure 3 are the differences between the observed and calculated (o−c) values that are derived from these line lists (Supporting Information).…”

“…The value for 13 C 6 H of A 1 « ´21 cm ´1 can be considered consistent. 31 The spectra of the 2 Π ´2Π bands are compared with observations from matrix isolation data, which bear the advantage that a mass-analyzer stage selects the ionized radical species before depositing in a matrix. In this way the matrix data provide an additional constraint that can be used to identify the carriers of the bands discussed here.…”