Cross sections for the reactions of Ar+ with H2, D2, and HD to form ArH+ ArD+ are measured using a new guided ion beam tandem mass spectrometer which affords an experimental energy range from 0.05 500 eV laboratory. The apparatus techniques described in detail. H2 D2 found be nearly identical over this entire when compared at same barycentric energy. total cross section is as low energies, but differs significantly above 4 c.m., where product dissociation becomes important. intramolecular...

Negative ion photoelectron spectra of Cu−n, Ag−n(n=1–10), and Au−n (n=1–5) are presented for electron binding energies up to 3.35 eV at an instrumental resolution 6–9 meV. The metal cluster anions prepared in a flowing afterglow source with cold cathode dc discharge. In the Cu−2, Ag−2, Au−2, M2 X 1Σ+g←M−2 2Σ+u transitions vibrationally resolved. We analyze these yield adiabatic affinities, vibrational frequencies, bond length changes, dissociation energies. 3Σ+u triplet states Cu2 Ag2 also...

Analysis of the energy dependence cross sections for collision-induced dissociation reactions has permitted determination quantitative thermodynamic information a variety ionic clusters. As such clusters become larger, rate at which decomposition occurs becomes comparable to instrumental time available observing reaction. A method incorporating statistical theories energy-dependent unimolecular in this threshold analysis is reviewed and updated. The revision relies on fact that most...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBond strengths of ethylene and acetyleneKent M. Ervin, Scott Gronert, S. E. Barlow, Mary K. Gilles, Alex G. Harrison, Veronica Bierbaum, Charles H. DePuy, W. C. Lineberger, Barney EllisonCite this: J. Am. Chem. Soc. 1990, 112, 15, 5750–5759Publication Date (Print):July 1, 1990Publication History Published online1 May 2002Published inissue 1 July 1990https://pubs.acs.org/doi/10.1021/ja00171a013https://doi.org/10.1021/ja00171a013research-articleACS...

The X̃ 1A1, ã 3B2, and b̃ 3A2 states of vinylidene are observed in the ultraviolet (351.1–364.0 nm) photoelectron spectra 2B2 H2CC−, D2CC−, 2A′ HDCC−. 1A1 state exhibits vibrational structure well above barrier for isomerization to acetylene. A strict lower bound lifetime singlet against rearrangement is τ>0.027 ps, with an estimate τ≊0.04–0.2 ps based on a simulation line shapes including rotational broadening. analysis triplet bands provides frequencies estimates changes molecular...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltraviolet photoelectron spectrum of nitrite anionKent M. Ervin, Joe Ho, and W. C. LinebergerCite this: J. Phys. Chem. 1988, 92, 19, 5405–5412Publication Date (Print):September 1, 1988Publication History Published online1 May 2002Published inissue 1 September 1988https://pubs.acs.org/doi/10.1021/j100330a017https://doi.org/10.1021/j100330a017research-articleACS PublicationsRequest reuse permissionsArticle Views809Altmetric-Citations232LEARN ABOUT...

The ultraviolet photoelectron spectrum of O2- exhibits 29 resolved vibronic transitions to the three low-lying electronic states neutral O2 (X 3Σg-, a 1Δg, b 1Σg+) from X 2ΠJ (J = 3/2 and 1/2) spin−orbit anion. A Franck−Condon simulation, using established molecular constants oxygen states, matches every observed feature in spectrum. 0−0 origin transition is unambiguously assigned, yielding electron affinity EA0(O2) 0.448 ± 0.006 eV. derived bond dissociation energy D0(O2-) 395.9 0.6 kJ/mol....

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of Copper Group Cluster Anions with Oxygen and Carbon MonoxideTaeck Hong Lee Kent M. ErvinCite this: J. Phys. Chem. 1994, 98, 40, 10023–10031Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October 1994https://pubs.acs.org/doi/10.1021/j100091a014https://doi.org/10.1021/j100091a014research-articleACS PublicationsRequest reuse permissionsArticle Views979Altmetric-Citations206LEARN...

Theoretical calculations and experimental values from the recent literature are used to construct evaluate a high precision gas-phase acidity scale. Gas-phase acidities at 0 K evaluated for 12 reference species with accurately known acidities. Using spectroscopic results, small but significant revisions presented of ammonia, water, formaldehyde. These revised anchor applied previous thermokinetic or equilibrium measurements alkanols, ethene, benzene. Combined electron affinities negative ion...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoelectron spectra of dicarbon(1-) and ethynyl(1-)Kent M. Ervin W. C. LinebergerCite this: J. Phys. Chem. 1991, 95, 3, 1167–1177Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://pubs.acs.org/doi/10.1021/j100156a026https://doi.org/10.1021/j100156a026research-articleACS PublicationsRequest reuse permissionsArticle Views598Altmetric-Citations165LEARN ABOUT THESE...

Negative ion photoelectron spectra of Ni−2, Pd−2, and Pt−2 are presented for electron binding energies up to 3.35 eV at an instrumental resolution 8–10 meV. The metal cluster anions prepared in a flowing afterglow source. Each dimer exhibits multiple low-lying electronic states vibrationally resolved ground state transition. Franck–Condon analyses yield the anion neutral vibrational frequencies bond length changes between neutral. affinities determined be EA(Ni2)=0.926±0.010 eV,...

The transition metal trimer anions Ni−3, Pd−3, and Pt−3 are prepared in a flowing afterglow ion source with cold cathode dc discharge. low-lying electronic states of the neutral trimers probed by 488 nm negative photoelectron spectroscopy at an electron kinetic energy resolution 5–12 meV. Each exhibits multiple states. Vibrational progressions observed tripalladium triplatinum. adiabatic affinities found to be EA(Ni3)=1.41±0.05 eV, EA(Pd3)≲1.5±0.1 EA (Pt3)=1.87±0.02 eV.

The naphthyl anion (C10H7-, naphthalenide) is prepared in a flow tube reactor by proton transfer between NH2- and naphthalene (C10H8). photoelectron spectrum of this measured at fixed laser wavelength 364 nm. A single electronic band observed, corresponding to the neutral radical (C10H7, naphthalenyl). Franck−Condon profiles for both 1-naphthyl (α-naphthyl) 2-naphthyl (β-naphthyl) are simulated on basis density functional theory calculations vibrational frequencies normal coordinates. Issues...

Ion chemistry, first discovered 100 years ago, has profitably been coupled with statistical rate theories, developed about 80 ago and refined since. In this overview, the application of theory to analysis kinetic-energy-dependent collision-induced dissociation (CID) reactions is reviewed. This procedure accounts for quantifies kinetic shifts that are observed as systems increase in size. The approach allows straightforward extension undergoing competitive or sequential dissociations. Such...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNegative ion photoelectron spectroscopy of halocarbene anions (HCF-, HCCl-, HCBr-, and HCI-); angular distributions neutral triplet excitation energiesMary K. Gilles, Kent M. Ervin, Joe Ho, W. C. LinebergerCite this: J. Phys. Chem. 1992, 96, 3, 1130–1141Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992https://doi.org/10.1021/j100182a021RIGHTS & PERMISSIONSArticle...

Catalysis of the oxidation reaction CO+12O2→CO2 by metal clusters is examined gas phase ion chemistry and mass spectrometry techniques. Small platinum cluster anions, Ptn− (n=3–6), are effective catalysts for under thermal conditions. The proposed mechanism involves atomic oxygen chemisorbed on clusters.

Guided ion beam tandem mass spectrometry techniques are used to examine promotion of the symmetric bimolecular nucleophilic substitution (SN2) reaction 37Cl- + CH335Cl → 35Cl- CH337Cl by translational energy. The energy threshold for this process is 45 ± 15 kJ/mol, well above previously reported potential barrier height 10−13 kJ/mol SN2 transition state. collisionally activated involves conventional back-side attack at carbon atom, but passage over impeded nonstatistical dynamical...

The threshold collision-induced dissociation method is applied to study the fragmentation patterns and measure energies of small anionic copper clusters (Cun−, n=2–8) their monocarbonyls (CunCO−, n=3–7). For bare clusters, main reaction channels are loss an atom a dimer. cluster monocarbonyls, channel CO. Dissociation for from anions, D0(Cun−1−–Cu), show even–odd alternation. species with highest energy, Cu7−, carbonyl desorption Cu5CO−, have eight valence electrons, consistent closed shells...

Experimental studies of the interactions small transition-metal cluster anions with carbonyl ligands are reviewed and compared neutral cationic clusters. Under thermal conditions, reaction rates clusters carbon monoxide measured as a function size. Saturation limits for addition can be related to geometric structures Both energy-resolved threshold collision-induced dissociation experiments time-resolved photodissociation used measure metal-carbonyl binding energies. For platinum palladium...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetal cluster ions: the bond energy of diatomic manganese(1+)K. Ervin, S. K. Loh, N. Aristov, and P. B. ArmentroutCite this: J. Phys. Chem. 1983, 87, 19, 3593–3596Publication Date (Print):September 1, 1983Publication History Published online1 May 2002Published inissue 1 September 1983https://pubs.acs.org/doi/10.1021/j100242a006https://doi.org/10.1021/j100242a006research-articleACS PublicationsRequest reuse permissionsArticle...

The reactions of N+(3P) ions with H2, HD, D2 are examined using guided ion beam tandem mass spectroscopy. Absolute reaction cross sections measured from near thermal energies to 30 eV relative energy. low energy section behavior is analyzed empirical threshold models and phase space theory. results compared other recent studies the N++H2 system. endothermicity for N+(3P)+H2→NH++H, ΔH○0 =0.033±0.024 (0.76±0.55 kcal/mol), bond NH+, D○0(N–H+) =3.51±0.03 (80.9±0.6 derived results.

Energy-resolved competitive collision-induced dissociation methods are used to measure the gas-phase acidities of a series alcohols (methanol, ethanol, 2-propanol, and 2-methyl-2-propanol). The reactions fluoride−alcohol, [F-·HOR], alkoxide−water, [RO-·HOH], alkoxide−methanol [RO-·HOCH3] proton-bound complexes studied using guided ion beam tandem mass spectrometer. reaction cross sections product branching fractions two proton transfer channels measured as function collision energy. enthalpy...