Infrared spectrum of the NH4-dn+ cation trapped in solid neon

Jacox, Marilyn E.; Thompson, Warren E.

doi:10.1039/b414641g

Cited by 14 publications

(8 citation statements)

References 42 publications

(49 reference statements)

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“…Given the already mentioned unsuitability of NH 4 + for radio astronomic detection, a search for this ion should be probably based on IR spectroscopy (see ref. 55 and references therein).…”

Section: Resultsmentioning

confidence: 99%

Proton transfer chains in cold plasmas of H₂with small amounts of N₂. The prevalence of NH₄⁺

Carrasco

Tanarro

Herrero

et al. 2013

Phys. Chem. Chem. Phys.

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“…Given the already mentioned unsuitability of NH 4 + for radio astronomic detection, a search for this ion should be probably based on IR spectroscopy (see ref. 55 and references therein).…”

Section: Resultsmentioning

confidence: 99%

Proton transfer chains in cold plasmas of H₂with small amounts of N₂. The prevalence of NH₄⁺

Carrasco

Tanarro

Herrero

et al. 2013

Phys. Chem. Chem. Phys.

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“…Despite the insight into structural details of the hydration of NH 3 and NH 4 + in solution provided by X-ray or neutron diffraction, − NMR spectroscopy, , QM/MD studies, − , gas-phase clusters spectroscopic studies, − ,,− and low-temperature solid matrix or crystalline studies, − ambiguities about the number and strength of hydrogen bonds to the solvent water, and the associated hydrogen bond dynamics, remain. This propels the necessity for further experimental evidence on the fundamental nature of hydrogen bonding of NH 3 and of NH 4 + in solution.…”

Section: Introductionmentioning

confidence: 99%

Aqueous Solvation of Ammonia and Ammonium: Probing Hydrogen Bond Motifs with FT-IR and Soft X-ray Spectroscopy

et al. 2017

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In a multifaceted investigation combining local soft X-ray and vibrational spectroscopic probes with ab initio molecular dynamics simulations, hydrogen-bonding interactions of two key principal amine compounds in aqueous solution, ammonia (NH) and ammonium ion (NH), are quantitatively assessed in terms of electronic structure, solvation structure, and dynamics. From the X-ray measurements and complementary determination of the IR-active hydrogen stretching and bending modes of NH and NH in aqueous solution, the picture emerges of a comparatively strongly hydrogen-bonded NH ion via N-H donating interactions, whereas NH has a strongly accepting hydrogen bond with one water molecule at the nitrogen lone pair but only weakly N-H donating hydrogen bonds. In contrast to the case of hydrogen bonding among solvent water molecules, we find that energy mismatch between occupied orbitals of both the solutes NH and NH and the surrounding water prevents strong mixing between orbitals upon hydrogen bonding and, thus, inhibits substantial charge transfer between solute and solvent. A close inspection of the calculated unoccupied molecular orbitals, in conjunction with experimentally measured N K-edge absorption spectra, reveals the different nature of the electronic structural effects of these two key principal amine compounds imposed by hydrogen bonding to water, where a pH-dependent excitation energy appears to be an intrinsic property. These results provide a benchmark for hydrogen bonding of other nitrogen-containing acids and bases.

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“…Available experimental results agree with the bonding character of the HOMO of NH 3 whose vibration frequency drops in

{NH}_{3}^{+}

from 3444 cm −1 to 3389 cm −1 (e) and from 3337 cm −1 to 3177 cm −1 (a 1 ) . Protonated species

{NH}_{4}^{+}

in Ne matrix absorbs at 3357.5 (e), very close to

{NH}_{3}^{+}

.…”

Section: Resultsmentioning

confidence: 98%

Bonding/antibonding character of “lone pair” molecular orbitals from their energy derivatives; consequences for experimental data

Chaquin

Fuster

Volatron

2018

Int J of Quantum Chemistry

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The derivative of molecular orbitals (MO) energies with respect to a bond length (dynamic orbital force [DOF]) is used to estimate the bonding/antibonding character of valence MOs along this bond, with a focus on lone pair MOs, in a series of small molecules: AH (A 5 F, Cl, Br), AH 2 (A 5 O, S, Se), AX 3 (A 5 N, P, As; X 5 H, F), and H 2 CO. The HOMO DOF agrees with the calculated variation of bond length and force constant in the corresponding ground state cation, and of bond length variation by protonation. These results also agree with available experimental data. It is worthy to note that the p-type HOMOs in AH and AH 2 are found bonding. The lone pair MO is bonding in NH 3 , while it is antibonding in PH 3 , AsH 3 , and AF 3 . K E Y W O R D S bonding/antibonding, lone pairs, molecular orbital force 1 | I N T R O D U C T I O N 1.1 | How to define the bonding/antibonding character of a MO?The bonding/antibonding character can be based on essentially two criteria, energy or force, with different possible definitions on these criteria.The IUPAC Gold Book [1] prefers the energy point of view, a bonding MO being characterized by "an increase in the total bonding." This generally corresponds also to a MO energy lower than the mean energy of the AOs constituting this MO. These definitions involve the whole molecule.Nevertheless, for the chemist, it is important to characterize local MO properties, that is, their bonding/antibonding character along a bond, or moreThe bonding/antibonding zones are, thus, characterized by a positive/negative value of the function f. They are separated by a nonbonding surface given in Figure 1 for a symmetrical A 2 molecules and the unsymmetrical HF one.On this basis, the total electron density is decomposed into MO densities and, thus, into additive orbital forces which quantify their bonding character. [3]-[5] Another concept of "orbital forces" was proposed by Tal and Katriel. [6] It is built up from the MO energy derivatives with respect to nuclear coordinates. According to the Koopmans theorem, [7] the MO energy can be expressed as Equation 2:Int J Quantum Chem. 2018;e25658. https://doi.The Table 1 indicates that 1r and 2r usually referred as r bonding MO and sp lone pair MO, respectively, are almost equally bonding. The p MOs, usually described as "purely nonbonding" have in fact a marked bonding character. This character is partly due to the presence of empty p MOs of hydrogen in an extended basis set. Nevertheless, even at the STO-3G level, this character remains (0.011 au for HF), though the overlap with the 1s AO of hydrogen is zero. It means that the pure atomic p density on atom A is intrinsically bonding, that is, exerts an attractive force on the H nucleus. It can be understood qualitatively from Figure 1: the nonbonding surface does not divide equally the 2p density which can be seen slightly more localized in the bonding region.The bonding character of p MOs agrees with the calculated bond lengths of neutral and cationic ( 2 p) species: in each case the cation HF 1 , ...

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Infrared spectrum of the NH4-dn+ cation trapped in solid neon

Cited by 14 publications

References 42 publications

Proton transfer chains in cold plasmas of H₂with small amounts of N₂. The prevalence of NH₄⁺

Proton transfer chains in cold plasmas of H₂with small amounts of N₂. The prevalence of NH₄⁺

Aqueous Solvation of Ammonia and Ammonium: Probing Hydrogen Bond Motifs with FT-IR and Soft X-ray Spectroscopy

Bonding/antibonding character of “lone pair” molecular orbitals from their energy derivatives; consequences for experimental data

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Infrared spectrum of the NH4-dn+ cation trapped in solid neon

Cited by 14 publications

References 42 publications

Proton transfer chains in cold plasmas of H2with small amounts of N2. The prevalence of NH4+

Proton transfer chains in cold plasmas of H2with small amounts of N2. The prevalence of NH4+

Aqueous Solvation of Ammonia and Ammonium: Probing Hydrogen Bond Motifs with FT-IR and Soft X-ray Spectroscopy

Bonding/antibonding character of “lone pair” molecular orbitals from their energy derivatives; consequences for experimental data

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Proton transfer chains in cold plasmas of H₂with small amounts of N₂. The prevalence of NH₄⁺

Proton transfer chains in cold plasmas of H₂with small amounts of N₂. The prevalence of NH₄⁺