The Dawn of Chemistry

Abstract

Within the precise cosmological framework provided by the Lambda-Cold Dark Matter model and standard Big Bang nucleosynthesis, the chemical evolution of the pregalactic gas can now be followed with accuracy limited only by the uncertainties on the reaction rates. Starting during the recombination era, the formation of the first molecules and molecular ions containing hydrogen, deuterium, helium, and lithium was severely hindered by the low density of the expanding universe, the intensity of the cosmic radiation field, and the absence of solid catalyzers. Molecular hydrogen and deuterated hydrogen, the most abundant species formed in the gas phase prior to structure formation, played a fundamental role in the cooling of the gas clouds that gave birth to the first stellar generation, contributing to determine the scale of fragmentation. Primordial molecules also interacted with the photons of the cosmic background via resonant scattering, absorption and emission. In this review we examine the current status of the chemistry of the early universe and discuss the most relevant reactions for which uncertainties still exist from theory or laboratory experiments. The prospects for detecting spectral distortions or spatial anisotropies due to the first atoms and molecules are also addressed.

To appear in Annual Review of Astronomy and Astrophysics, vol. 51

References in corpus (39)

• Primordial Nucleosynthesis in the Precision Cosmology Era
• Primordial Nucleosynthesis: from precision cosmology to fundamental physics
• The Primordial Lithium Problem
• The Formation of Population III Binaries from Cosmological Initial Conditions
• An extremely primitive halo star
• Metallicity Evolution of Damped Lyman-alpha Systems out to z~5
• Uncertainties in H2 and HD Chemistry and Cooling and their Role in Early Structure Formation
• The Formation of the First Stars II. Radiative Feedback Processes and Implications for the Initial Mass Function
• HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich
• Probing the Formation of the First Low-Mass Stars with Stellar Archaeology
• The primordial abundance of 4He: a self-consistent empirical analysis of systematic effects in a large sample of low-metallicity HII regions
• Deuterium Abundance in the Most Metal-Poor Damped Lyman alpha System: Converging on Omega_baryons
• HE 1327-2326, an unevolved star with [Fe/H]<-5.0. II. New 3D-1D corrected abundances from a VLT/UVES spectrum
• A new, precise measurement of the primordial abundance of Deuterium
• Science with a lunar low-frequency array: from the dark ages of the Universe to nearby exoplanets
• The Most Metal-Poor Stars. III. The Metallicity Distribution Function and CEMP Fraction
• How well do we understand cosmological recombination?
• Cosmic-ray and X-ray Heating of Interstellar Clouds and Protoplanetary Disks
• Formation of Massive Primordial Stars in a Reionized Gas
• Extremely metal-poor gas at a redshift of 7
• Is H3+ cooling ever important in primordial gas?
• Star Formation in the First Galaxies I: Collapse Delayed by Lyman-Werner Radiation
• The impact of dark matter decays and annihilations on the formation of the first structures
• Primordial helium recombination I: feedback, line transfer, and continuum opacity
• Effects of primordial chemistry on the cosmic microwave background
• Vibrational level population of H${}_2$ and H${}_2^{+}$ in the early Universe
• The Impact of HD Cooling on the Formation of the First Stars
• Observation of interstellar lithium in the low-metallicity Small Magellanic Cloud
• The influence of magnetic fields on the thermodynamics of primordial star formation
• Cosmological production of H_2 before the formation of the first galaxies
• Deuterium at high-redshift: Primordial abundance in the zabs = 2.621 damped Ly-alpha system towards CTQ247
• Primordial helium recombination III: Thomson scattering, isotope shifts, and cumulative results
• Recombination of H3+ Ions in the Afterglow of a He-Ar-H2 Plasma
• 6Li/7Li estimates for metal-poor stars
• Rotational quenching rate coefficients for H_2 in collisions with H_2 from 2 to 10,000 K
• Molecular fluorine chemistry in the early Universe
• Spectral Spatial Fluctuations of CMBR: Strategy and Concept of the Experiment
• LiHe${}^{+}$ in the early Universe: a full assessment of its reaction network and final abundances
• HD molecule and search for early structure-formation signatures in the Universe

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• First astrophysical detection of the helium hydride ion (HeH${}^{+}$)
• When did Population III star formation end?
• The importance of magnetic fields for the initial mass function of the first stars
• The Spectrum of the Universe
• Gravitational waves from Population III binary black holes formed by dynamical capture
• Seeding the Second Star: enrichment from population III, dust evolution, and cloud collapse
• Supermassive Black Holes in the Early Universe
• The Hydrodynamic Feedback of Cosmic Reionization on Small-Scale Structures and Its Impact on Photon Consumption during the Epoch of Reionization
• Astrochemistry: overview and challenges
• Starbursts in low-mass haloes at Cosmic Dawn. I. The critical halo mass for star formation
• Molecule formation in dust-poor irradiated jets I. Stationary disk winds
• Detection of vibrational emissions from the helium hydride ion (HeH${}^{+}$) in the planetary nebula NGC 7027
• Survey of ortho-H${}_2$D${}^{+}$ in high-mass star-forming regions
• Controlling rotational quenching rates in cold molecular collisions
• Review of scientific topics for Millimetron space observatory
• Early structure formation from primordial density fluctuations with a blue-tilted power spectrum
• Molecular Chemistry for Dark Matter
• Dissipation of magnetic fields in star-forming clouds with different metallicities
• Primordial star formation: relative impact of H2 three-body rates and initial conditions
• Modelling the cosmological Lyman-Werner background radiation field in the Early Universe
• Population III star formation in an X-ray background: III. Periodic radiative feedback and luminosity induced by elliptical orbits
• Vibrational excitation and dissociation of deuterium molecule by electron impact
• The role of the H${}_2$ adiabatic index in the formation of the first stars
• HI-to-H${}_2$ Transitions in Dust-Free Interstellar Gas
• Ionization degree and magnetic diffusivity in the primordial star-forming clouds
• Global radiation signature from early structure formation
• Impact of Population III homogeneous stellar evolution on early cosmic reionisation
• Energy-transfer Quantum Dynamics of HeH${}^{+}$ with He atoms: Rotationally Inelastic Cross Sections and Rate Coefficients
• Extending the view of ArH+ chemistry in diffuse clouds
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• Exploring the Possibility of Identifying Hydride and Hydroxyl Cations of Noble Gas Species in the Crab Nebula Filament
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• Thermal and Resonant Emission of Dark Ages Halos in the Rotational Lines of HeH${}^{+}$
• Influence of a quasi-molecular mechanism of recombination on the formation of hydrogen in the early universe
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• Temperature and density dependent cooling function for H${}_2$ with updated H${}_2$/H collisional rates
• Molecules in the early Universe
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• Mapping the Universe in HD
• Halos in Dark Ages: formation and chemistry
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• Potential contributions of Pop III and intermediate-mass Pop II stars to cosmic chemical enrichment
• Quantum mechanical study of the high-temperature ${\mathrm{H}}^{+}+\mathrm{HD}\to {\mathrm{D}}^{+}+{\mathrm{H}}_2$ reaction for the primordial universe chemistry
• Initial Li Abundances in the Protogalaxy and Globular Clusters Based upon the Chemical Separation and Hierarchical Structure Formation
• Ionization degree and magnetic diffusivity in star-forming clouds with different metallicities
• Redshifted 21-cm emission signal from the halos in Dark Ages
• Globular clusters as cosmic clocks: new cosmological hints from their integrated light
• Can the quasi-molecular mechanism of recombination decrease the Hubble tension?
• Non-thermal photons and direct photodissociation of H2, HD and HeH+ in the chemistry of the primordial Universe
• Revisiting the statistical equilibrium of H${}^{-}$ in stellar atmospheres
• Rydberg States of H${}_3$ and HeH as Potential Coolants for Primordial Star Formation
• The oldest Milky Way stars: New constraints on the age of the Universe and the Hubble constant
• Condition for low-mass star formation in shock-compressed metal-poor clouds
• Interrelations between Astrochemistry and Galactic Dynamics
• Direct Collapse Black Hole Candidates from Decaying Dark Matter
• The Fine-Tuning Argument
• Development of a glow-discharge ion-trap instrument for measuring effective radiative-association rate coefficients