منابع مشابه
Tunnelling in carbonic acid.
The cis,trans-conformer of carbonic acid (H2CO3), generated by near-infrared radiation, undergoes an unreported quantum mechanical tunnelling rotamerization with half-lives in cryogenic matrices of 4-20 h, depending on temperature and host material. First-principles quantum chemistry at high levels of theory gives a tunnelling half-life of about 1 h, quite near those measured for the fastest ro...
متن کاملAqueous carbonic acid (H2CO3).
Carbonic acid (H2CO3) is a molecule right at the interface between organic and inorganic chemistry. In fact, according to some definitions it is an organic molecule, while according to others it is an inorganic molecule. Its exceptionality can also be recognized from the fact that it formally belongs neither to the mononor dicarboxylic acids, even though it is a C1 diprotic acid. The diprotic n...
متن کاملExperiments with a high-density positronium gas.
We have created a high-density gas of interacting positronium (Ps) atoms by irradiating a thin film of nanoporous silica with intense positron bursts and measured the Ps lifetime using a new single-shot technique. When the positrons were compressed to 3.3 x 10(10) cm-2, the apparent intensity of the orthopositronium lifetime component was found to decrease by 33%. We believe this is due to a co...
متن کاملDissociation of carbonic acid: gas phase energetics and mechanism from ab initio metadynamics simulations.
A comprehensive metadynamics study of the energetics, stability, conformational changes, and mechanism of dissociation of gas phase carbonic acid, H2CO3, yields significant new insight into these reactions. The equilibrium geometries, vibrational frequencies, and conformer energies calculated using the density functional theory are in good agreement with the previous theoretical predictions. At...
متن کاملSpectroscopic observation of matrix-isolated carbonic acid trapped from the gas phase.
Carbonic acid (H2CO3) is of fundamental importance, for example, for regulation of blood pH, in the acidification of the oceans, and in the dissolution of carbonates. This six-atom molecule commonly found in carbonated drinks in submicromolar concentrations has so far eluded most attempts at isolation and direct detection. Despite the widespread belief that it is a highly instable molecule, the...
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ژورنال
عنوان ژورنال: Scientific American
سال: 1910
ISSN: 0036-8733
DOI: 10.1038/scientificamerican12031910-444