Results 71 to 80 of about 40,404 (274)

Photodissociation and chemistry of N$_2$ in the circumstellar envelope of carbon-rich AGB stars [PDF]

A&A 568, A111 (2014), 2014
The envelopes of AGB stars are irradiated externally by ultraviolet photons; hence, the chemistry is sensitive to the photodissociation of N$_2$ and CO, which are major reservoirs of nitrogen and carbon, respectively. The photodissociation of N$_2$ has recently been quantified by laboratory and theoretical studies.
arxiv   +1 more source

Molecular ion trap-depletion spectroscopy of BaCl$^+$

, 2011
We demonstrate a simple technique for molecular ion spectroscopy. BaCl$^+$ molecular ions are trapped in a linear Paul trap in the presence of a room-temperature He buffer gas and photodissociated by driving an electronic transition from the ground X$^1 ...
Chen, Kuang, Hudson, Eric R., Kotochigova, Svetlana, Petrov, Alexander, Rellergert, Wade G., Schowalter, Steven J., Sullivan, Scott T.   +6 more
core   +1 more source

Short-lived metal-centered excited state initiates iron-methionine photodissociation in ferrous cytochrome c

Nature Communications, 2021
The dissociation mechanism of the heme axial ligand in heme proteins is not yet fully understood. The authors investigate the photodissociation dynamics of the bond between heme Fe and methionine S in ferrous cytochrome c using femtosecond time-resolved ...
Marco E. Reinhard, Michael W. Mara, Thomas Kroll, Hyeongtaek Lim, Ryan G. Hadt, Roberto Alonso-Mori, Matthieu Chollet, James M. Glownia, Silke Nelson, Dimosthenis Sokaras, Kristjan Kunnus, Tim Brandt van Driel, Robert W. Hartsock, Kasper S. Kjaer, Clemens Weninger, Elisa Biasin, Leland B. Gee, Keith O. Hodgson, Britt Hedman, Uwe Bergmann, Edward I. Solomon, Kelly J. Gaffney   +21 more
doaj   +1 more source

State resolved data for radiative association of H and p and for photodissociation of H${}_2^+$ [PDF]

ApJS 216 (2015), 21, 2014
The matrix elements and energies needed to calculate vibrational-rotational state resolved cross sections and rate coefficients for radiative association of H and p and for photodissociation of H${}_2^+$ are presented for applications to simulations of chemistry in the early Universe and to stellar atmospheres.
arxiv   +1 more source

Photodissociation of the OD radical at 226 and 243 nm [PDF]

, 2003
The photodissociation dynamics of state selected OD radicals has been examined at 243 and 226 nm using velocity map imaging to probe the angle–speed distributions of theD(2S) and O(3P2) products.
Chestakov, Dmitri A., Eppink, Andre T.J.B., Greenslade, Margaret E., Groenenboom, Gerrit G., Lester, Marsha I., Parker, David H., Radenovic, Dragana C., ter Meulen, J J., van der Loo, Mark P.J., van Roij, Andre J.A.   +9 more
core   +1 more source

Photodissociation and the Morphology of HI in Galaxies

, 2004
Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this ``back-reaction'', atomic hydrogen \HI is one of the easiest to ...
A Sternberg, AN Witt, BG Elmegreen, DA Smith, DJ Hollenbach, DJ Hollenbach, EJ Shaya, GB Field, J-M Deharveng, JE Pringle, JM Shull, L Vigroux, MG Wolfire, MG Wolfire, MJ Kaufman, O Laurent, R Braun, R Braun, RJ Allen, RJ Allen, RJ Allen, RJ Allen, RJ Allen, SC Madden, TP Stecher   +24 more
core   +2 more sources

Near-UV photolysis cross sections of CH₃OOH and HOCH₂OOH determined via action spectroscopy [PDF]

Atmospheric Chemistry and Physics, 2007
Knowledge of molecular photolysis cross sections is important for determining atmospheric lifetimes and fates of many species. A method and laser apparatus for measurement of these cross sections in the near-ultraviolet (UV) region is described.
C. M. Roehl, Z. Marka, Z. Marka, J. L. Fry, J. L. Fry, P. O. Wennberg, P. O. Wennberg   +6 more
doaj  

H i in Molecular Clouds: Irradiation by FUV Plus Cosmic Rays

The Astrophysical Journal, 2023
We extend the analytic theory presented by Sternberg et al. and Bialy & Sternberg for the production of atomic hydrogen (H i ) via far-ultraviolet (FUV) photodissociation at the boundaries of dense interstellar molecular (H _2 ) clouds to also include ...
Amiel Sternberg, Shmuel Bialy, Alon Gurman   +2 more
doaj   +1 more source

Photodissociative Regulation of Star Formation in Metal-Free Pregalactic Clouds [PDF]

, 1999
We study the H2 photodissociation regions around OB stars in primordial gas clouds whose virial temperatures are between a few hundred and a few thousand Kelvin. In such small objects, a single O star can photodissociate a mass equal to that of the cloud itself. As a result, the clouds deplete their molecular coolant and cannot cool in a free-fall time,
arxiv   +1 more source

On the photodissociation of H2 by the first stars [PDF]

Mon.Not.Roy.Astron.Soc. 321 (2001) 385-397, 2000
The first star formation in the universe is expected to take place within small protogalaxies, in which the gas is cooled by molecular hydrogen. However, if massive stars form within these protogalaxies, they may suppress further star formation by photodissociating the H2.
arxiv   +1 more source