Heats of formation of GeH4, GeF4 and Ge(CH3)4

Koizumi, Hideya; Dávalos, Juan Z.; Baer, Tomas

doi:10.1016/j.chemphys.2005.11.002

Cited by 21 publications

(39 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For germane, H 4 Ge, Simoes et al listed the enthalpy of formation as 90.8 ± 2.1 kJ/mol which is nearly identical to the value obtained by Green and Gunn of 90.4 ± 2.1 kJ/mol through combustion measurements . Baer and co-workers calculated the enthalpy of formation of H 4 Ge through a CCSD(T)/CBS method that included corrections for core valence and scalar relativistic effects . Their calculated enthalpy of formation of 82 kJ/mol matches well with our value of 80.4 kJ/mol.…”

Section: Resultssupporting

confidence: 88%

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes

2019

View full text Add to dashboard Cite

Hexamethylditin has been reported to be a more effective precursor compared to monotin analogs in hybrid molecular beam epitaxy depositions of perovskite oxides. To understand the differences, a library of 68 monotin-and ditincontaining molecules bearing hydrido and/or carbon-based ligands was generated, and their structures were optimized using density functional theory. On the basis of a modified W1-F12 composite thermochemical method, thermochemical data (enthalpy of formation, entropy, and heat capacity) were calculated for each structure over a range of temperatures (298− 5000 K). The application of the modified W1-F12 method to heavy element compounds was benchmarked against existing experimental and computational studies of mononuclear hydrido, alkyl, and mixed hydridoalkyl complexes of silicon, germanium, and tin. The library of thermodynamic data was used in partial equilibrium calculations from 300 to 1500 K to determine gas phase compositions resulting from the pyrolysis of tetramethyltin and hexamethylditin at 10 −6 and 760 Torr.

show abstract

Section: Resultssupporting

confidence: 88%

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes

2019

View full text Add to dashboard Cite

show abstract

“…The experimental value is uncertain, but Ruscic et al 80 argue that D 0 will be less than 85.5 kcal/mol. Koizumi et al 93 estimate the contribution of core−valence correlation and relativistic effects in GeH 4 to be only about 1 kcal/mol per bond, so it is likely that this value is too low. The SCGVB bond energy, 78.78 kcal/mol, is 10.31 kcal/mol less than that from the RCCSD(T) calculations.…”

Section: The Journal Of Physical Chemistry Amentioning

confidence: 99%

Spin-Coupled Generalized Valence Bond Description of Group 14 Species: The Carbon, Silicon and Germanium Hydrides, XH_n (n = 1–4)

Thompson

Dunning

2019

J. Phys. Chem. A

View full text Add to dashboard Cite

Although elements in the same group in the Periodic Table tend to behave similarly, the differences in the simplest Group 14 hydridesXH n (X = C, Si, Ge; n = 1−4)are as pronounced as their similarities. Spin-coupled generalized valence bond (SCGVB) as well as coupled cluster [CCSD(T)] calculations are reported for all of the molecules in the CH n /SiH n / GeH n series to gain insights into the factors underlying these differences. It is found that the relative weakness of the recoupled pair bonds of SiH and GeH gives rise to the observed differences in the ground state multiplicities, molecular structures, and bond energies of SiH n and GeH n . A number of factors that influence the strength of the recoupled pair bonds in CH, SiH, and GeH were examined. Two factors were identified as potential contributors to the decrease in the strengths of these bonds from CH to SiH and GeH: (i) a decrease in the overlap between the orbitals involved in the bond and (ii) an increase in Pauli repulsion between the electrons in the two lobe orbitals centered on the X atoms. Finally, an analysis of the hybridization of the SCGVB orbitals in XH 4 indicates that they are closer to sp hybrids than sp 3 hybrids, which implies that the underlying cause of the tetrahedral structure of the XH 4 molecules is not a direct result of the hybridization of the X atom orbitals.

show abstract

“…On the other hand, the stability of the parent ion increases considerably among the silicon analogues, in which all of the Si(CH 3 ) 3 X + ions are stable. 35,36 This trend continues up to germanium, 37,38 and tin, which is the subject of this study.…”

Section: Introductionmentioning

confidence: 85%

Dissociation of energy selected Sn(CH3)4+, Sn(CH3)3Cl+, and Sn(CH3)3Br+ ions: evidence for isolated excited state dynamics

Baer

Guerrero

Dávalos

et al. 2011

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

The dissociation dynamics of Sn(CH 3 ) 4 + , Sn(CH 3 ) 3 Cl + , and Sn(CH 3 ) 3 Br + were investigated by threshold photoelectron photoion spectrometry using an electron imaging apparatus (iPEPICO) at the Swiss Light Source. The tetramethyltin ion was found to dissociate via Sn(CH 3 ) 4 + -Sn(CH 3 ) 3 + + CH 3 -Sn(CH 3 ) 2 + + 2 CH 3 , while the trimethyltin halide ions dissociated via methyl loss at low energies, and a competitive halogen loss at somewhat higher energies. The 0 K methyl loss onset for the three ions was found to be 9.410 AE 0.020 eV, 10.058 AE 0.020 eV, and 9.961 AE 0.020 eV, respectively. Statistical theory could not reproduce the observed onsets for the halogen loss steps in the halotrimethyltin ions. The halide loss signal as a function energy mimicked the excited state threshold photoelectron spectrum, from which we conclude that the halide loss from these ions takes place on an isolated excited state potential energy surface, which we describe by time dependent density functional calculations.The sequential loss of a second methyl group in the Sn(CH 3 ) 4 + ion, observed at about 3 eV higher energies than the first one, is also partially non-statistical. The derived product energy distribution resulting from the loss of the first methyl group is two-component with about 50% being statistical and the remainder associated with high translational energy products that peak at 2 eV. Time dependent DFT calculations show that a dissociative B ˜state lies in the vicinity of the experimental measurements. We thus propose that 50% of the Sn(CH 3 ) 4 + ions produced in this energy range internally convert to the X ˜state, on which they dissociate statistically, while the remainder dissociate directly from the repulsive B ˜state leading to high kinetic energy products.

show abstract

Heats of formation of GeH4, GeF4 and Ge(CH3)4

Cited by 21 publications

References 53 publications

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes

Spin-Coupled Generalized Valence Bond Description of Group 14 Species: The Carbon, Silicon and Germanium Hydrides, XH_n (n = 1–4)

Dissociation of energy selected Sn(CH3)4+, Sn(CH3)3Cl+, and Sn(CH3)3Br+ ions: evidence for isolated excited state dynamics

Contact Info

Product

Resources

About

Heats of formation of GeH4, GeF4 and Ge(CH3)4

Cited by 21 publications

References 53 publications

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes

Computational Thermochemistry of Mono- and Dinuclear Tin Alkyls Used in Vapor Deposition Processes

Spin-Coupled Generalized Valence Bond Description of Group 14 Species: The Carbon, Silicon and Germanium Hydrides, XHn (n = 1–4)

Dissociation of energy selected Sn(CH3)4+, Sn(CH3)3Cl+, and Sn(CH3)3Br+ ions: evidence for isolated excited state dynamics

Contact Info

Product

Resources

About

Spin-Coupled Generalized Valence Bond Description of Group 14 Species: The Carbon, Silicon and Germanium Hydrides, XH_n (n = 1–4)