Electronic Structure Predictions of the Energetic Properties of Tellurium Fluorides

Abstract

The heats of formation, bond dissociation energies (BDEs), fluoride affinities (FA), fluorocation affinities (FCA), electron affinities (EA), and ionization energies (IP) of TeF n (n = 1−6) have been predicted using the Feller−Peterson−Dixon (FPD) approach. To benchmark the approach, the bond dissociation energies of Te 2 and TeO, the heats of formation of Te 2 , TeH 2 , TeO, and TeO 2 , and the electron affinity for TeO and TeO 2 were calculated as there are experimental thermodynamic data available for these tellurium compounds, which allow confirmation of the heat of formation of Te gas as ΔH f,0K (Te) = 50.7 ± 0.6 kcal/mol. Spin−orbit corrections are required for good results and cannot be ignored. A comparison among fluoride affinities, fluorocation affinities, electron affinities, and ionization energies of TeF n and SeF n is reported.

Bond Dissociation Energies in Heavy Element Chalcogen and Halogen Small Molecules

“…For Te 2 as noted previously, the agreement with the experiment (61.73, 62.3 ± 0.2, 62.4, 61.3 ± 1.1, and 60.64 kcal/mol) for the BDE is excellent as long as care is taken for the spin–orbit correction. For Se 2 , the calculated BDE of 77.5 kcal/mol is consistent with a value of 3.411 eV (78.7 kcal/mol) from the higher atomic state dissociation limit and with the BDEs from photoionization and thermochemical mass spectrometry/Knudsen cell experiments. ,− Our calculated value is not consistent with the value of D 0 0 of 3.1638 eV (73.0 kcal/mol) from the predissociation of the B­(1 u ) and B­(0 u + ) states .…”

“…The COSCI calculations for Se 2 indicate that the HF determinant for the Ω = 0 g + state contributes only 66%; hence, multireference effects are significant for this molecule when SO is included. We have previously examined the spin–orbit correction for the Te 2 BDE in some detail. Using twice the correction for the Te atom minus one-half of the zero-field splitting of Te 2 gives a spin–orbit correction of −9.2 kcal/mol, which is consistent with the current CCSD­(T) and AoC-DHF values of −9.47 and −8.75 kcal/mol, respectively.…”

“…These corrections are required for agreement with experiment. In a similar way, the spin–orbit correction for Te 2 is 7.8 kcal/mol with a multiplet averaging of 9.2 kcal/mol for the atoms . Data for the different spin–orbit states of some of the open-shell diatomic molecules is available from the experiment and is also given in Table .…”

Oxidative Fluorination of Selenium and Tellurium Compounds using a Thermally Stable Phosphonium SF5−Salt Accessible from SF6

“…To rank the stability of the obtained anions with respect to fluoride abstraction, [26] we calculated the fluoride ion affinity (FIA) of the corresponding Lewis acids EF 4 and PhEF 3 using the method reported by Christe and co‐workers (Table 1). [25] TeF 4 has the highest FIA in this series, [27] which is ranked between those of BF 3 and PF 5 and explains the low tendency of TeF 5 − to react with water. Formal substitution of a fluorine atom by a phenyl group (PhTeF 3 ) or of tellurium with selenium (SeF 4 ) both decreases the FIA by about 50 kJ mol −1 .…”

A high level theory investigation on the lowest-lying ionization potentials of glycine (NH2CH2COOH)

“…In this work, a computational investigation on the lowest-lying IPs of the NH 2 CH 2 COOH molecule was carried out through the use of the high-level equation-of-motion ionization potential coupled-cluster with single and double excitations method (EOMIP-CCSD) 51 combined with the Feller-Peterson-Dixon (FPD) composite approach. 52 As the FPD method represents a well established composite procedure for determining accurate IPs and has been applied to a multitude of chemical systems, providing results that are in excellent agreement (within 1.0 kcal mol −1 ) in regards to experimental values, 53,54 it is expected that the outcomes from the present work may provide reliable information for performing the modeling of several photoinduced processes. In addition, this work may also be of assistance in terms of helping experimentalists in eventual future identification of glycine conformations.…”