Search results
Results from the WOW.Com Content Network
Unlike the helium hydride ion, the neutral helium hydride molecule HeH is not stable in the ground state. However, it does exist in an excited state as an excimer (HeH*), and its spectrum was first observed in the mid-1980s. [19] [20] [21] The neutral molecule is the first entry in the Gmelin database. [4]
The helium hydride ion HeH + has been known since 1925. [70] The protonated dihelium ion He 2 H + can be formed when the dihelium cation reacts with dihydrogen: He + 2 + H 2 → He 2 H + + H. This is believed to be a linear molecule. [70] Larger protonated helium cluster ions exist He n H + with n from 3 to 14. He 6 H + and He 13 H + appear to ...
[2] The spectrum of a particular molecule is governed by the selection rules of quantum chemistry and by its molecular symmetry. Some molecules have simple spectra which are easy to identify, whilst others (even some small molecules) have extremely complex spectra with flux spread among many different lines, making them far harder to detect. [3]
The spectrum of molecules has advantages over atomic spectral lines, as atomic lines are often very strong, and therefore only come from high in the atmosphere. Also the profile of the atomic spectral line can be distorted due to isotopes or overlaying of other spectral lines. [ 6 ]
It was not until 1980 that the first spectrum of H + 3 was discovered by Takeshi Oka, [6] ... Dihydrogen cation, H + 2; Helium hydride ion, [HeH] + References
The helium hydride ion, thought to be the earliest molecule to have been formed in the Universe (about 100,000 years after the Big Bang), was detected in 2019 for the first time in space in NGC 7027. [ 21 ] [ 22 ] There is also evidence for the presence of nanodiamond in NGC 7027.
The simplest is the helium hydride molecular ion, HeH +, discovered in 1925. [59] Because it is composed of the two most abundant elements in the universe, hydrogen and helium, it was believed to occur naturally in the interstellar medium, and it was finally detected in April 2019 using the airborne SOFIA telescope.
A laboratory gas-phase spectrum of C 60 + was obtained in 2015 by a group led by John Maier. [21] Their results matched the band wavelengths that had been observed by Foing and Ehrenfreund in 1994. [21] Three weaker bands of C 60 + were found in interstellar spectra soon afterwards, resolving one of the earlier objections raised by Jenniskens. [22]