BP86 Methods Research Articles

Benchmarking boron cluster calculations: Establishing reliable geometrical and energetic references for Bn (n = 1-4).

Using full configuration interaction (FCI) and multi-reference configuration interaction methods (MRCI), reliable geometrical and energetic references for Bn (n = 1-4) clusters were established. The accuracy of the computed results was confirmed by comparison with available experimental data. Benchmark calculations indicated that B97D3, B97D, VSXC, HCTH407, BP86 and CCSD(T) methods provided reasonable results for structural parameters, with mean absolute error (MAEs) within 0.020 Å. Among the tested density functional theory (DFT) methods, the VSXC functional showed the best performance in predicting the relative energies of B1 B4 with a MAE of 12.8 kJ mol-1 . Besides, B1B95, B971, TPSS, B3LYP, and BLYP functionals exhibited reasonable performance with MAE values of less than 15.0 kJ mol-1 . T1 diagnostic values between 0.035 and 0.109 at the CCSD(T) level revealed strong correlations in B2 B4 clusters, highlighting the need for caution in using CCSD(T) as an energy reference for small boron clusters. The methods of CCSDT, CCSDT(Q) and CCSDT[Q], which incorporate three-electron and four-electron excitations, effectively improved the accuracy of the energy calculations.

Investigation on formation mechanisms of PBDD/Fs from 2,6-dibromophenol pyrolysis using density functional theory (DFT) method

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) are the potential persistent organic pollutants in the environment. A comprehensive understanding of the formation and evolution mechanisms of PBDD/Fs contributes to better control their emissions. In this paper, the formation mechanisms of PBDD/Fs from 2,6-dibromophenol pyrolysis were investigated, and the kinetic and thermodynamic parameters in all formation pathways were calculated through using density functional theory (DFT) method B3P86 with the 6-311 + G(d,p) basis set. The calculation results show that the 2-bromophenoxy radical is a major decomposition product in initial pyrolysis of 2,6-dibromophenol, and dimerization of bromophenoxy radicals occurs mainly through O-C coupling or C-C coupling. O-C coupling results in the formation of PBDD precursors, and C-C coupling results in the formation of PBDF precursors. The formation of PBDD/Fs proceeds mainly via H-abstraction or H-transfer, cyclization, and debromination or dehydroxylation. The energy barriers of rate-determining steps in the formation of PBDDs are lower than those of PBDFs, so the formations of brominated dibenzo-p-dioxins are superior to the formations of brominated dibenzofurans.

Orbital character and vibrational spectra study on carbon monoxide and nitrosyl compound Mn(NO)3CO

The geometry, electronic structure, energy and vibrational spectra of Mn(NO) 3 CO have been studied using B3P86, B3LYP and B3PW91 methods at 6-31G basis set level. Three states have been found and all states have been fully investigated employing the molecular orbital theory and vibrational analysis. From the calculation, we have found that the singlet state is the most stable one.

Theoretical Studies on the Structures of Metal String Complexes Crn(L)4Cl2 (n = 3, 5, 7; L = Oligo-α-Pyridylamide) under the Effect of an Electric Field.

To study the electronic structures and properties of [Crn(L)4Cl2] (n = 3, L = dpa: di(2-pyridyl)amido; n = 5, L = tpda: tripyridyldiamido; n = 7, L = teptra: tetrapyridyltriamine) metal string complexes, the BP86 method was used by considering the influence of the electric field (EF) applied parallel to the metal axis. As the EF increases, the migration of more positively charged Crodd is more significant than that of Creven, which results in alternating long-short Cr-Cr bonds. This happens because of the natural charges on the Crodd of 1-3, which are more electropositive than those on Creven. The electrons are pulled to the Cr and Cl(r) atoms at the high-potential side from Cl(l) at the low-potential side by the EF, which leads to asymmetrical FMOs. After the critical electric field (Ec), the configuration turns into a remarkably asymmetric one with alternating Cr-Cr quadruple bonds and weak interactions. The electrons are transferred from equatorial ligands (L) to metal chains. In the meantime, the asymmetry of the FMOs increases and the delocalization is further reduced, which affects the conductivity. Especially for [Cr7(teptra)4Cl2], the delocalized electrons of HOMO are completely transformed into a localized model after the critical electric field. It is observed that this supports the electric switching phenomenon ascribed to the conformations of delocalized and localized electrons. In addition, the longer the length of the metal chain, the smaller the Ec and the easier is for the complexes to be polarized by the EF.

Ab initio study of spectroscopic properties at anharmonic force fields of LiNH2.

This work presents a systematic investigation of the spectroscopic properties at anharmonic force fields of ground electronic state ([Formula: see text]) of LiNH2, which are calculated using second-order Møller-Plesset perturbation theory (MP2) and density functional theory (DFT) with hybrid GGA and meta-hybrid GGA (M06-2X) exchange-correlation functional. Two high angular momentum basis sets of 6-311+g (2d, p) and 6-311++g (3df, 2pd) are used. The equilibrium geometries, ground-state rotational constants, harmonic frequencies, and quartic and sextic centrifugal distortion constants of LiNH2 are calculated and compared with corresponding experimental or theoretical data. The predicted accuracy of the calculated constants has been confirmed by analyzing the deviations with respect to experiment. In addition, the anharmonic constants, vibration-rotation interaction constants, force constants, and Coriolis coupling constants of LiNH2 are firstly obtained. The infrared spectrum is predicted and together with the first prediction on the higher-order anharmonic constants contributes to a better understanding of the vibrational and rotational characteristics of LiNH2, thus revealing its internal structure. Graphical abstract The IR spectra and the magnified IR spectra at 3500 cm-1 in harmonic approximations of LiNH2 using B3P86, M06-2X and MP2 methods combining with 6-311++g(3df,2pd).

Theoretical Study of the Structure and Ionization Potentials of Proline

Eight conformations of proline have been found considering two conformations of carboxyl group and the location of hydrogen atom at the nitrogen atom. Adiabatic and vertical ionization potentials have been determined employing B3LYP, B3P86, and B3PW91 methods with 6-311++G** basis set. Vertical ionization potentials have been determined using the older outer-valence Green’s function (OVGF) and the partial third-order (P3) quasiparticle approximation of the electron propagator with 6-311++G** basis set. Adiabatic and vertical ionization potentials in water have been calculated using the polarized continuum model (PCM) at B3LYP/6-311++G** level. The conformer with the lowest energy has been found and analyzed in detailed.

Spectroscopic constants and anharmonic force fields of F2SO: An ab inito study

The equilibrium geometry, spectroscopic constants and anharmonic force field of F2SO (X∼1A′) have been reported employing B3LYP, B3P86, B3PW91 and MP2 methods combining with Dunning’s correlation-consistent cc-pVQZ, cc-pV5Z, aug-cc-pVQZ and aug-cc-pV5Z basis sets. The calculated equilibrium geometry, equilibrium rotational constants and fundamental vibrational frequencies of F2SO well reproduce the previous theoretical or experimental values. The calculated equilibrium geometry verifies that F2SO has pyramidal structure and Cs symmetry instead of C1 symmetry. The ground-state rotational constants, harmonic vibrational frequencies, anharmonic constants, quartic and sextic centrifugal distortion constants, cubic and quartic force constants, vibration-rotation interaction constants, and Coriolis coupling constants of F2SO are also predicted. The calculated results show that B3P86 and MP2 methods are superior to B3LYP and B3PW91 methods for the spectroscopic constants of F2SO, we hope that our predictions can provide the useful data for the experiment study of the corresponding spectroscopic constants of F2SO.

Theoretical investigation of selected hydrogenated germanium clusters (Ge5Hn, n = 0–12) from density functional theory calculations

ABSTRACTWe reported the selected hydrogen absorption of Ge5Hn isomers and their Ge5Hn− anions in the size range of n = 0–12 for the first time by B3LYP, BPW91, BHandHLYP and BP86 methods in combination with 6-311++G** basis sets. The optimum geometrical structure, relative stability, electronic properties and dissociation behaviour of Ge5Hn (n = 0–12) cluster and their Ge5Hn− anions were systematically analysed by a series of methods and can be applied to the study of more complex cluster systems. H bridged structure and double H bridged structures were found in the size range of n = 1–6 in neutral clusters and corresponding anion with triangular bipyramidal framework of Ge5. The visible odd-even oscillations were observed in the study of change rules with increasing size from the Δ2E(n), H-dissociation energy (De), HOMO–LUMO band-gap (Egap) and electron affinity (EA) energy. This conclusion indicated that Ge5Hn clusters with even H atoms were more stable than clusters with odd H atoms. The infrared spectra of the Ge5Hn (n = 0–12) clusters were also simulated which will further stimulate study on germanium-based nanomaterials.

Binuclear heterometallic bonding between a first row transition metal and a second row transition metal: The cyclopentadienyliron molybdenum carbonyls Cp2FeMo(CO)n (n = 6, 5, 4, 3, 2)

The geometries and energetics of the heterometallic binuclear cyclopentadienyl iron-molybdenum carbonyls Cp2FeMo(CO)n (n = 6, 5, 4, 3, 2; Cp = η5-C5H5), including the experimentally known pentacarbonyl Cp2FeMo(CO)5 have been examined by density functional theory. The lowest energy structure for the pentacarbonyl Cp2FeMo(CO)5 by the mPWPW19 method corresponds to the unbridged Cp2FeMo(CO)5 isomer related to the experimental Cp2Mo2(CO)6 structure with exclusively terminal carbonyl groups. However, the doubly bridged structure, which is related to the experimental trans- and cis-Cp2Fe2(CO)2(µ-CO)2 structures of the homonuclear diiron derivative, lies only 1.4 kcal/mol in energy above the unbridged structure. The relative energies of the unbridged and doubly bridged Cp2FeMo(CO)5 are reversed using the BP86 method with the doubly bridged structure lying 2.0 kcal/mol below the unbridged structure. The closeness in energy of these two structures suggests a fluxional system for Cp2FeMo(CO)5. The low-energy structures for the tetracarbonyl Cp2FeMo(CO)4 are doubly bridged structures with formal Fe=Mo double bonds in accord with the 18-electron rule. However, Cp2FeMo(CO)4 is predicted not to be viable since its disproportionation into Cp2FeMo(CO)5 + Cp2FeMo(CO)3 is found to be highly exothermic. The tricarbonyl Cp2FeMo(CO)3 has an energetically favorable triply bridged structure with a formal Fe≡Mo triple bond analogous to the experimental valence isoelectronic Cp*2M2(µ-CO)3 (M = Mn, Re; Cp* = η5-Me5C5) structures. The low-energy structures of the dicarbonyl Cp2FeMo(CO)2 are doubly bridged structures which can be either singlets with an FeMo quadruple bond or triplets with an Fe≡Mo triple bond. The low-energy structures of the hexacarbonyl Cp2FeMo(CO)6 can be interpreted as consisting of [CpFe(CO)3]+ cations linked to [CpMo(CO)3]− anions through one of the iron-bonded carbonyl groups with long ∼4 Å Fe⋯Mo distances indicating the absence of an iron-molybdenum bond.

Structure and vibrational spectra of p-coumaric acid dimers by DFT methods

We performed a systematic investigation to determine the most accurate DFT functional in the prediction of geometrical parameters and vibrational frequencies for p-coumaric acid (p-CA). For this purpose, we followed a multi-dimensional strategy by performing calculations with 8 DFT functionals for the p-CA dimer with fine and ultrafine grids. We also compared scaled and unscaled harmonic frequencies of p-CA with experimental ones. The unscaled BP86 harmonic frequencies were the most accurate relative to the experimental ones but the BP86 method had the lowest accuracy for the structural parameters. The dispersion-corrected method, wB97XD, showed the best performance for the geometries of the p-CA dimer, though it yielded the highest RMSDs for the vibrational frequencies. We observed that the methods PBE0/def2-TZVP and M06-2X/def2-TZVP, with an ultrafine grid, provided a cost-effective approach which predicted accurately both geometrical parameters and scaled vibrational frequencies of p-CA.

A theoretical study on 1H/13C/31P NMR chemical shifts, and the correlation between 2JP–H and the electronic structure of different phosphoryl benzamide derivatives

A comprehensive study was performed on 1H/13C/31P NMR chemical shifts (CSs) of some phosphoryl benzamide derivatives (R1C6H5C(O)NHP(O)R2R3), [R1 = CH3, OCH3, NO2, F, Cl, Br and R1, R2 = NHC(CH3)3 or NC4H8O] by the GIAO method to find the most correlated level of theory with experimental values. All the structures (C1C12) were firstly optimized at B3LYP, BP86, PBE1PBE, M06-2X, MPWB1K and MP2 methods with 6–31 + G* basis set. Computed structural parameters demonstrate that BP86 has the best agreement to experimental values. The def2-TZVP and aug-cc-pVDZ basis sets were also employed to inspect the effect of different basis sets. The correlation between experimental and computational values prove that 6–31 + G* basis set is the optimum case regarding minimization of the costs and results. Chemical shifts were calculated at all mentioned combinations and compared with experimental data, which demonstrate that in accordance with structural parameters, BP86/6−31 + G* gives the best results. Calculating 2JPH values of studied compounds, focusing on the comparison between experimental and theoretical results was another aim of this study. Computed values of 2JPH at the optimum level of theory reveal an acceptable agreement with experimental data. Eventually, the dependency between 2JPH values and the bonding structures was inspected. NBO analysis at BP86/6−311++G** explicates the relationship between the electronic properties of studied compounds and 2JPH values.

Toward the comprehensive calculations on the relationship between 1 H, 13 C, 31 P chemical shifts, 2 JPH , and the bonding structure of different phosphoryl benzamides.

A comprehensive investigation was performed on 1 H, 13 C, and 31 P nuclear magnetic resonance (NMR) chemical shifts (CSs) of phosphoryl benzamide derivatives (C6 H5 C(O)NHP(O)R1 R2 ), (R1 , R2 =aziridine [L1 ], azetidine [L2 ], pyrrolidine [L3 ], piperidine [L4 ], azepane [L5 ], 4-methylpiperidine [L6 ], propane-2-amine [L7 ], and 2-methylpropane-2-amine [L8 ]) by the gauge-independent atomic orbital method (GIAO) to find the most accordant level of theory with the experimental values. To achieve this goal, all the structures were optimized using the B3LYP, BP86, PBE1PBE, M06-2X, MPWB1K, and MP2 methods with 6-31+G* basis set. Computed structural parameters demonstrate that BP86 has the best agreement to the experimental values between the other methods. The def2-TZVP and aug-cc-pVDZ basis sets were also employed to inspect the effect of different types of basis sets with higher polarization and diffuse functions. The correlation between the empirical and computational values attests that 6-31+G* basis set is the optimum case regarding minimization of the costs and results. The comparison between calculated and experimental CSs at all mentioned combinations illustrated that in accordance with structural results, the best level of theory in CSs is also BP86/6-31+G*. Besides, 2 JPH values were computed with an acceptable agreement to experimental data at the optimum level of theory. The dependency between 2 JPH and the bonding structure of studied ligands was also scrutinized by the Natural Bond Orbital (NBO) analysis that interprets the relationship between the electronic properties and 2 JPH values.

Activation and recyclization of a benzocyclobutenone derivative catalyzed by a chiral Rh(I) complex based on DFT investigations

The R- and S-activation and cyclization channels of an achiral benzocyclobutenone derivative to a pair of enantiomers with poly-fused rings were investigated systematically based on full optimization with the BP86 functional in gas phase and the M06 functional in tetrahydrofuran (THF). Both the BP86 and M06 methods show that the R-channel is energetically more favorable than the S-channel in gas phase and in THF. The rate-determining step for the R-channel is the C–C activation with a barrier of 17.2 kcal/mol in THF and 11.8 kcal/mol in gas phase, but for the S-channel, the rate-determining step is the pentatomic ring formation process with a barrier of 25.6 kcal/mol in THF and 22.3 kcal/mol in gas phase.

Influencing Mechanism of Carbonyl and Thiophene on Cranial Nerve Based on Their Bridging and Steric Hindrance Effects on Titanium Coordination Compound

This paper aims to disclose the damage or repair mechanism of carbonylation and thiophene on cranial nerves. To this end, the bonding pattern of binuclear titanium carbonyls with thiophene was investigated by two methods of density functional theory (DFT), namely, the B3LYP method and the BP86 method. Then, 8 stable isomer structures were found for binuclear titanium carbonyls with thiophene, including 5 doublet structures and 3 triplet structures. These structures were discussed in details and the energy needed to dissociate each of them into mononuclear fragments was calculated through the thermochemistry analysis. The results show that the Ti2(C4H3S)m(CO)n structures are linked by 2.8~3.6 A-long Ti-Ti bonds. The bonds are relatively long and considered as formal single bonds. Every structure of the binuclear titanium carbonyls with thiophene is bridged by CO group or C4H3S group and sometimes dibridged by both the CO group and C4H3S group. The energy to dissociate Ti2(C4H3S)2(CO)6 into Ti(C4H3S)2(CO)2 and Ti (CO)4 fragments is 71.4kcal/mol (B3LYP)/ 89.6kcal/mol (P86), higher than that to dissociate the other Ti2(C4H3S)m(CO)n structures into Ti(C4H3S)i(CO)j fragments. The electron structure of the Ti atom in Ti2(C4H3S)2(CO)6 is 17-electron structure, the nearest to the 18-electron structure. The research findings provide important insights into the influencing mechanism of carbonyl and thiophene on caranial nerve.

DFT calculations for anharmonic force field and spectroscopic constants of YC2 and its 13C isotopologues

The construction of the complete third and the semi-diagonal quartic force fields including the anharmonicity of the ground state (X˜2A1) for yttrium dicarbide (YC2) is carried out employing the vibrational second-order perturbation theory (VPT2) in combination with the density functional theory (DFT). The equilibrium geometries optimization, anharmonic force field and vibrational spectroscopic constants of YC2 are calculated by B3LYP, B3PW91 and B3P86 methods. Aug-cc-pVnZ (n=D, T, Q) and cc-pVnZ-PP (n=D, T, Q) basis sets are chosen for C and Y atoms, respectively. The calculated geometry parameters of YC2 agree well with the corresponding experimental and previous theoretical results. The bonding characters of YC2 or CC are discussed. Based on the optimized equilibrium geometries, the spectroscopic constants and anharmonic force field of YC2 are calculated. Comparing with the spectroscopic constants of YC2 derived from the experiment, the calculated results show that the B3PW91 and B3P86 methods are superior to B3LYP for YC2. The Coriolis coupling constants, cubic and quartic force constants of YC2 are reasonably predicted. Besides, the spectroscopic constants and anharmonic force field of Y13C2 (X˜2A1) and Y13CC (X˜2A′) are calculated for the first time, which are expected to guide the high resolution experimental work for YC2 and its 13C isotopologues.

Ab Initio Studies on Spectroscopic Constants for the HAsO Molecule.

The anharmonic force fields and spectroscopic constants of the electronic ground state (X̃1A') for the HAsO molecule are reported employing the MP2, B3LYP, B3P86, and B3PW91 methods with cc-pVQZ and cc-pV5Z basis sets. The calculated molecular geometries, rotational constants, vibrational frequencies, and anharmonic constants of the HAsO molecule are compared with the experimental data. It is found that the best agreement between the calculated results and experiment data is at the B3LYP/cc-pV5Z theoretical level. The predicted cubic and quartic force fields, vibration-rotation interaction constants, quartic and sextic centrifugal distortion constants, and Coriolis coupling constants of the HAsO molecule at the B3LYP/cc-pV5Z theoretical level are expected to be reliable.

Coordination chemistry and bonding analysis of tetranuclear transition metal pyrene sandwich complexes

Geometry optimizations have been performed on the M4(Pyr)2 (M = Ti-Ni, Pd and Pt, Pyr = C16H10) complexes by means of DFT method using BP86 and mPW1PW91 functionals combined to the TZP basis set. The M4 moiety encapsulated between two pyrene ligands tends to establish M-L bonding with various hapticies from η2 to η6. In accordance with the coordination modes, the pyrene behaves as neutral, dianionic, or tetraanionic ligand. For the Ti, V, and Fe, the low-spin (S = 0) and the high-spin (S = 1) structures are isoenergetic, while the Cr, Mn, and Co structures prefer the high-spin states. The Ni, Pd, and Pt structures are more favorable in low-spin state. The zigzag metallic chain is predicted to be more stable than that of the two-dimensional sheet for the Pd complexes. The spin state changes of the studied complexes in their ground states could be characterized in some cases by different molecular structure modifications (structural isomerisation, where structural modifications accompany the spin state modification like as bonds and angles), electronic configurations (low-spin or high-spin), or oxidation states with respect to the metal charges, in agreement with the metal nature. The optimized structures obtained by both BP86 and mPW1PW91 methods are consistent to each other, where the energetic parameters follow similar tendencies regarding the stability order between isomers.

The benchmark of 31P NMR parameters in phosphate: a case study on structurally constrained and flexible phosphate.

A benchmark for structural interpretation of the 31P NMR shift and the 2JP,C NMR spin-spin coupling in the phosphate group was obtained by means of theoretical calculations and NMR measurements in diethylphosphate (DEP) and 5,5-dimethyl-2-hydroxy-1,3,2-dioxaphosphinane 2-oxide (cDEP). The NMR parameters were calculated employing the B3LYP, BP86, BPW91, M06-2X, PBE0, KT2, KT3, MP2, and HF methods, and the 6-31+G(d), Iglo-n (n = II, III), cc-pVnZ (n = D, T, Q, 5), aug-cc-pVnZ (n = D, T and Q), and pcS-n and pcJ-n (n = 1, 2, 3, 4) bases, including the solvent effects described with explicit water molecules and/or the implicit Polarizable Continuum Model (PCM). The effect of molecular dynamics (MD) on NMR parameters was MD-calculated using the GAFF force field inclusive of explicit hydration with TIP3P water molecules. Both the optimal geometries and the dynamic behaviors of the DEP and cDEP phosphates differed notably, which allowed a reliable theoretical benchmark of the 31P NMR parameters for highly flexible and structurally constrained phosphate in a one-to-one relationship with the corresponding experiment. The calculated 31P NMR shifts were referenced employing three different NMR reference schemes to highlight the effect of the 31P NMR reference on the accuracy of the calculated 31P NMR shift. The relative Δδ(31P) NMR shift calculated employing the MD/B3LYP/Iglo-III/PCM method differed from the experiment by 0.16 ppm while the NMR shifts referenced to H3PO4 and/or PH3 deviated from the experiment notably more, which illustrated the superior applicability of the relative NMR reference scheme. The 2JP,C coupling in DEP and cDEP calculated employing the MD/B3LYP/Iglo-III(DSO,PSO,SD)/cc-PV5Z(FC)/PCM method inclusive of correction due to explicit hydration differed from the experiment by 0.32 Hz and 0.15 Hz, respectively. The NMR calculations demonstrated that reliable structural interpretation of the 31P NMR parameters in phosphate must involve both the structural and the dynamical components.

Assessment of Contemporary Theoretical Methods for Bond Dissociation Enthalpies

The density functional theory (DFT) is the most popular method for evaluating bond dissociation enthalpies (BDEs) of most molecules. Thus, we are committed to looking for alternative methods that can balance the computational cost and higher precision to the best for large systems. The performance of DFT, double-hybrid DFT, and high-level composite methods are examined. The tested sets contain monocyclic and polycyclic aromatic molecules, branched hydrocarbons, small inorganic molecules, etc. The results show that the mPW2PLYP and G4MP2 methods achieve reasonable agreement with the benchmark values for most tested molecules, and the mean absolute deviations are 2.43 and 1.96 kcal/mol after excluding the BDEs of branched hydrocarbons. We recommend the G4MP2 is the most appropriate method for small systems (atoms number≤20); the double-hybrid DFT methods are advised for large aromatic molecules in medium size (20≤atoms number≤50), and the double-hybrid DFT methods with empirical dispersion correction are recommended for long-chain and branched hydrocarbons in the same size scope; the DFT methods are advised to apply for large systems (atoms number≥50), and the M06-2X and B3P86 methods are also favorable. Moreover, the differences of optimized geometry of different methods are discussed and the effects of basis sets for various methods are investigated.

Quantum Chemical Study of the Low-Lying Electronic States of VSi3(-/0) Clusters and Interpretation of the Anion Photoelectron Spectrum.

The geometrical and electronic structures of VSi3(-/0) clusters have been investigated with the DFT, CCSD(T), and CASSCF/CASPT2 methods. The results showed that the suitable functional to identify the ground states of VSi3(-/0) clusters is not the B3LYP but the BP86. At the BP86, CCSD(T), and CASPT2 levels, the ground state of the anionic cluster was the (1)A' ((1)A1) of tetrahedral η(3)-(Si3)V(-) isomer, while that of the neutral cluster was the 1(2)A' and 1(2)A″ (1(2)E) of the same isomer. The 1(2)A' and 1(2)A″ of the tetrahedral η(3)-(Si3)V isomer were the results of the Jahn-Teller distortions of the 1(2)E in C3v symmetry. All three bands in the photoelectron spectrum of the VSi3(-) cluster were interpreted by one-electron detachments from the (1)A' anionic ground state on the basis of the BP86, CCSD(T), and CASPT2 methods. The calculated adiabatic and vertical detachment energies were in agreement with the experimental values. The broad shape of the first band was explained by Franck-Condon factor simulations for the (1)A' → 1(2)A' and (1)A' → 1(2)A″ transitions within the tetrahedral η(3)-(Si3)V(-/0) isomers.