Anton Batalov

Electronic absorption spectra of B3 and B3− in neon matrices and ab initio analysis of the vibronic structure

Mass selected B3− ions have been isolated in 6 K neon matrices and their absorption spectra measured. A band system with origin at 467 nm is assigned as the 1E′←X 1A1′ electronic transition of the cyclic anion. After photobleaching, the 1 2E′←X 2A1′ and 2 2E′←X 2A1′ band systems of neutral cyclic B3 are observed which start around 736 and 458 nm, respectively. Large scale ab initio calculations have provided potential energy surfaces for a variational treatment of the vibrational motion. Calculated band origins leave no doubt about the electronic symmetry assignments. The complex vibrational structure in the 1 2E′ state, which is due to relatively strong Jahn–Teller distortions, appears to be closely reproduced by the calculated vibrational energies and intensities, if the first observed stronger line is identified with the first vibrationally excited state, placing the “true” band origin of the 1 2E′ state at 775 nm where no signal with significant strength is apparent. The 2 2E′ state undergoes only a r...

High-resolution electronic spectroscopy of a nonlinear carbon chain radical C6H4+

A high-resolution gas-phase spectrum of a molecular absorption band around 604 nm is assigned as due to an electronic transition of a nonlinear C6H4+ planar species starting from its 2A″ electronic ground state. The spectrum is observed in direct absorption by cavity ringdown spectroscopy through a supersonic planar discharge through a mixture of acetylene in helium. The spectrum has a clear rotational and K-type structure. This allows an accurate determination of the B and C rotational constants and an estimate for the A rotational constant in ground and electronically excited states. The resolved spectrum of the fully deuterated species C6D4+ has been obtained as well. The results are compared both to the outcome of ab initio geometry optimizations and low-resolution absorption spectra in 6 K neon matrices obtained after mass-selective deposition.

Electronic and infrared absorption spectra of linear and cyclic C6+ in a neon matrix.

Electronic and infrared absorption spectra of mass-selected C6+, generated by dissociative electron impact ionization of C6Cl6 and C6Br6, have been recorded in 6 K neon matrices. Linear and cyclic forms of C6+ have been observed. The 2Pig<--Chi2Piu electronic transition of linear C6+ has its origin band at 646 nm whereas for the (2) 2B2<--Chi2A1 system of the cyclic isomer it lies at 570 nm. An infrared active fundamental mode in the ground electronic state of C6+ is observed at 2092 and 1972 cm(-1) for the linear and cyclic isomer, respectively.

Electronic absorption spectra of linear and cyclic Cn+n=7–9 in a neon matrix

The C(n)(+) n=7-9 cations were produced by electron-impact ionization of perchloronaphthalene, mass selected, and their electronic absorption spectra in 6 K neon matrices recorded. The linear and cyclic isomers of C7(+) and C8(+) are detected. Three systems of linear C7(+) are observed with origin bands near 770, 332, and 309 nm. The cyclic C7(+) shows two transitions near 676 and 448 nm. One system of linear C9(+) is observed commencing at 371 nm. Linear C8(+) shows five dipole-allowed electronic transitions from the X 2pi(g) ground state, and the strongest ones have the origin bands at 890.8 and 308.1 nm. Five electronic transitions of cyclic C8(+) are also discernible.