Formation and infrared spectra of monohydrogenated pyrenes 2-C16H11 and 4-C16H11 trapped in solid para-hydrogen

Abstract

We recorded the IR spectra of 2-C16R11 and 4-C16R11 trapped in solid para-hydrogen (p-H-2). These species were produced on the electron bombardment of p-H-2 containing pyrene (C16H10) in a small proportion during matrix deposition. IR absorption features of 1-C16H11+ and 1-C16H11 in solid p-H-2 were previously identified [J. Phys. Chem. Lett. 4 (2013) 1989]. Here, the irradiation of a similar matrix sample at 365 nm depleted 1-C(16)H(11)(+ )and 2-C16H11 and produced 1-C16H11 and 4-C16H11. In contrast, irradiation at 405 nm decreased 1-C16H11+, 2-C16H11 and 4-C16H11. The identification of the observed lines of 2-C16H11, and 4-C16H11 was supported by predictions of the vibrational wavenumbers and relative IR intensities at the B3PW91/6-311++G(2d,2p) level of theory. (C) 2020 Elsevier B.V. All rights reserved.