Spectroscopy of Carbon Vapor Condensed in Rare-Gas Matrices at 4° and 20°K. I

Abstract

The molecules vaporizing from graphite at 2300° to 2600 0 K have been trapped in neon, argon, and xenon matrices at 4° and 200K. The near-ultraviolet bands of Ca, beginning at 4050 A in the gas, have been observed in the absorption spectra of these matrices but shifted to 4057 A in neon, 4102 A in argon, and 4226 A in xenon. The neon spectrum is strikingly similar to low-temperature gaseous spectra, including cometary spectra, but the matrix bands occur in groups about 100 cm-I wide. The infrared spectrum yields a strong band at 2038 cm-1 in argon (2042 cm-1 in neon) which is assigned to va", the asymmetric stretching frequency of Ca in the ground electronic state. When the argon matrix is allowed to warm up, diffusion occurs, and larger carbon molecules, C 4 , C I , Cs, etc., are formed, causing the appearance of many new bands in the infrared. The Swan bands of C2 are observed in neon and argon matrices, but only after some annealing of the matrix has occurred by warming. The vibrational frequency of C2 in the excited 3JI" state in a neon matrix is 2094 cm-I , exceeding the value found in any other matrix or in the gas (1750 em-I). The possible appearance of C2 in its I~/ ground state in neon and argon matrices is briefly discussed. I

Chemical Evolution of a Co Ice Induced by Soft X-Rays

“…However, a larger numberof new species would also imply a larger destruction of the CO sample that is not detected (Figure 9). Elastic collisions between electrons contribute significantly to Holland et al (1988), Maier et al (1988) Hinkle et al (1988), Weltner et al (1964) 2018C 3 10 Hutter et al (1994 C 9 L Broad peak, Kurtz & Huffman (1990), Vala et al (1988 Gerakines et al (1995) the heating as the fractional ionization increases. At the same time, the mean energies for ionization, excitation, and dissociation increase approximately as the ionization fraction, and eventually all the initial electron energy is converted into heat (see, e.g., Dalgarno et al 1999 for a gas of solar composition).…”

Carbon‐Rich Compounds: Acetylene‐Based Carbon Allotropes

“…Thereafter, larger clusters C n (n j 4) were detected as linear species both in the gas phase and in solid rare gas matrices. In the early 1960s, Weltner and co-workers pioneered the matrix isolation spectroscopy of trapped carbon vapor molecules in rare gas solids such as solid Ar and Ne and found various electronic and vibrational transitions [2]. In the 1980s, guided by the infrared frequency obtained by matrix isolation spectroscopy, rotationally resolved spectra were measured in the gas phase by diode laser spectroscopy, from which the size n of linear C n could be deduced in order to provide unequivocal assignment of the vibrational transitions.…”

“…Some infrared absorption lines were further identified for the mass-selected clusters in Ne matrices [7]. For the mass-selected anions trapped in Ne matrices, the electronic absorption spectra of C 2n -(n = 2-7) [8a, 8b] and of C 2n + 1 -(n = [2][3][4][5] [8c], and also the emission of C 4 - [9] were reported. Surface plasmon polariton-enhanced Raman spectra (SERS) were obtained for size-selected C 2n (n = 7-10) clusters in nitrogen matrices and compared with the calculated vibrational frequencies for the ring and linear chain isomers [10].…”

“…The assignment of bands by analogy with the literature [5,6,27,28]. The relatively sharp peak with an asterisk at 407 nm is the A 1 P u nX 1 S g + transition of C 3 [1,2,4,28]. Note that the band of linear C 13 at Z380 nm [5c] is superimposed with relatively sharp absorption features of linear C 4 [6].…”

Laboratory simulation of heavy-ion cosmic-ray interaction with condensed CO

“…The C 3 molecule was identified by the 2039 cm −1 line (Weltner et al 1964;Jacox & Milligan 1974;Cermak et al 1998). In the current experiment, this peak rises early (F = 1 × 10 10 cm −2 ) in the spectrum and disappears at high fluences (F = 8.75 × 10 12 cm −2 ) where the bands for complex molecules start to be come visible.…”