Quantum Chemical Frequency Calculations Research Articles

Silane activation by laser-ablated Be atoms: Formation of HBeSiH3 and HBe(μ-H)3Si molecules

Laser-ablated beryllium atoms have been reacted with silane molecules during condensation in excess neon and argon at 4K. Absorptions due to HBeSiH3 and HBe(μ-H)3Si were observed and identified on the basis of isotopic IR spectroscopy, deuterium substitution with SiD4, and quantum chemical frequency calculations. The observed results show excited Be atom (1P1:2s12p1) can insert into SiH bond spontaneously and the insertion product rearranges to HBe(μ-H)3Si upon photolysis. The electron localization function (ELF) analysis suggests that 3c-2e hydrogen bridge bond (BeHSi) was formed by the donation of electrons for SiH σ bond to the empty p orbital of Be atom for HBe(μ-H)3Si molecule, which shows much difference from CH bond complexes.

Infrared spectrum of the chloromethylene hydroperoxide cation in solid argon

Infrared spectrum of the chloromethylene hydroperoxide cation, HC(Cl)OOH+ in solid argon is reported. The cation is produced by co-condensation of dichloromethane and dioxygen mixtures with high-frequency discharged argon at 4K followed by visible light excitation. On the basis of isotopic substitutions as well as quantum chemical frequency calculations, absorptions at 3452.7, 3052.0, 1499.6, 976.9, 855.4 and 956.1cm−1 are assigned to the O–H, C–H, CO, C–Cl and O–O stretching and out-of-plane CH wagging vibrations of the chloromethylene hydroperoxy cation. The cation was predicted to have a singlet ground state with planar Cs symmetry.

Infrared Spectra of Chlorinated Ethylene Cations: C2Cl4+, C2HCl3+, 1,1-C2H2Cl2+, and trans-C2H2Cl2+ in Solid Argon

Infrared spectra of chlorinated ethylene cations: C2Cl4+, C2HCl3+, 1,1-C2H2Cl2+, and trans-C2H2Cl2+ isolated in solid argon are presented. These cations were produced by co-deposition of chlorinated ethylene/Ar mixtures with high-frequency-discharged Ar at 4 K. Photosensitive absorptions are assigned to different vibrational modes of the cations on the basis of observed chlorine isotopic shifts and quantum chemical frequency calculations. With the removal of one electron from the HOMO of chlorinated ethylene neutrals that is C=C bonding and C-Cl antibonding in character, the observed C-Cl stretching vibrational frequencies of the cations are blue-shifted relative to those of the chlorinated ethylene neutrals. The results also show that the cations can be regarded as "isolated" with the vibrational frequencies only slightly shifted when compared to the available gas-phase values.

Experimental and theoretical characterization of a C2H2O2+ cation in solid argon

Laser ablation of transition metals with concurrent codeposition of C2H2/O2/Ar mixtures at 11 K produced metal independent absorptions at 1493.1 cm−1. On the basis of isotopic shifts and splittings, enhancement in doping with electron trapping gas, and quantum chemical frequency calculations, the band is assigned to the O–O stretching vibration of the C2H2O2+ cation, which was predicted to have a 2A″ ground state with a nonplanar Cs symmetry.

Infrared Spectra of the Novel Ge2H2 and Ge2H4 Species and the Reactive GeH1,2,3 Intermediates in Solid Neon, Deuterium and Argon

Laser-ablated Ge atoms and H2 molecules in excess neon and argon react during condensation to produce GeH1,2,3,4 as identified from infrared spectra with D2 and HD substitution, and from agreement with frequencies determined in recent gas-phase GeH and GeH2 fluorescence spectra and DFT calculations. The novel digermanium species Ge2H2 and Ge2H4 are formed in further reactions. Identification of Ge2H2 with the dibridged structure and Ge2H4 in the trans-bent C2h form is made possible by isotopic substitution and quantum chemical frequency calculations, which demonstrate the value of a close working relationship between experiment and theory. The photosensitive GeH3- anion is formed through electron capture by a GeH3 radical. All four germanium deuterides are observed in pure deuterium, which shows that further GeD and GeD2 reactions with D2 may require activation energy.