Investigations of Silicon−Nitrogen Hydrides from Reaction of Nitrogen Atoms with Silane: Experiments and Calculations

Abstract

Using a quadrupole mass filter and vacuum-ultraviolet ionization, we measured the time-of-flight spectra of species at mass-to-charge ratios of m/ z = 45-42 from the reaction of N + SiH 4 in crossed molecular beams. Species with m/ z = 44 and 43 correspond to reaction products HSiNH/SiNH 2 and HSiN/HNSi, respectively; species with m/ z = 45 and 42 are assigned to isotopic variants and daughter ions, respectively, of those two reaction products. We measured the photoionization yields and branching ratios for dissociative ionization of reaction products as a function of photoionization energy. The ionization thresholds of products HSiNH/SiNH 2 and HSiN/HNSi were determined to be 6.7 and 9.2 eV, respectively. Furthermore, we calculated the equilibrium structures, electronic energies, and vibrational wavenumbers of various silicon-nitrogen hydrides H x SiNH y ( x + y = 0-3) using quantum-chemical methods. SiNH 2 (X (2)B 2) and HNSi (X (1)Sigma (+)) are more stable than HSiNH (X (2)A') and HSiN (X (1)Sigma (+)) by 0.82 and 2.81 eV, respectively. SiNH 2 (X (2)B 2), HSiNH (X (2)A'), HNSi (X (1)Sigma (+)), and HSiN (X (1)Sigma (+)) have adiabatic ionization energies of 6.81, 8.19, 10.21, and 10.23 eV, respectively. These experimental and calculated results indicate that SiNH 2 (X (2)B 2) and HNSi (X (1)Sigma (+)) are dominant among isomeric products in the reaction of N + SiH 4. This work presents the first observation of products from the reaction of N + SiH 4 in crossed beams and extensive calculations on pertinent silicon-nitrogen hydrides.

Directed Gas-Phase Formation of Aminosilylene (HSiNH2;X1A′): The Simplest Silicon Analogue of an Aminocarbene, under Single-Collision Conditions

“…With respect to the molecular hydrogen loss channel, the doublet radicals aminosilylidyne (SiNH 2 , p1 , C 2v , X 2 B 2 ), imidogensilylene (HSiNH, p2 , C s , X 2 A′), and imidogensilyl (H 2 SiN, p5 , C 2 v , X 2 B 2 ) can be formed in bimolecular reactions with reaction energies of −117, −43, and +90 kJ mol –1 , respectively. The relative energies of the products are in excellent agreement with earlier computational studies. ,, These data reveal that imidogensilyl (H 2 SiN, p5 , C 2 v , X 2 B 2 ) is energetically not accessible. Therefore, the consecutive discussion centers on the channels forming p1 to p3 .…”

“…The relative energies of the products are in excellent agreement with earlier computational studies. 23,34,35 These data reveal that imidogensilyl (H 2 SiN, p5, C 2v , X 2 B 2 ) is energetically not accessible. Therefore, the consecutive discussion centers on the channels forming p1 to p3.…”

Exploring the dynamics of reaction N(2D)+C2H4 with crossed molecular-beam experiments and quantum-chemical calculations

“…2 A nitrogen atom in state 2 D has a radiative lifetime of 17 h, 1 which makes feasible the reaction of atomic N( 2 D) with other molecules in experiments. Thus, most studies on reaction dynamics of nitrogen atoms were devoted to the reactions of 2 D nitrogen atoms with H 2 /D 2 , 3-5 H 2 O, 6 CH 4 , [7][8][9] SiH 4 , 10,11 C 2 H 2 , 12,13 and C 2 H 4 . [14][15][16] Reactions started with an insertion mechanism of N( 2 D) atoms into bonds H-H, CH 3 -H and SiH 3 -H to form reaction complexes H-N-H, CH 3 -N-H and SiH 3 -N-H, as well as an addition mechanism to the p-bond of CHRCH and CH 2 QCH 2 to form cyclic complexes c-CH(N)CH and c-CH 2 (N)CH 2 , respectively.…”

Explicitly correlated treatment of H2NSi and H2SiN radicals: Electronic structure calculations and rovibrational spectra

“…Experimentally, H 2 NSi species and related ions were identified in the mass spectrometric investigations of Goldberg et al, 18 using the flowing afterglow selected ion flow tube technique, 19 and after reactive collisions between N and SiH 4 , 20,21 and between silicon cation, Si + , and ammonia and small amines. 22 These identifications were supported by density functional theory and ab initio calculations.…”

“…22 These identifications were supported by density functional theory and ab initio calculations. 18,20,21,[23][24][25][26][27] In the present study, we map the six-dimensional potential energy surfaces (6D-PESs) of the formaldehyde-like isomers (i.e., H 2 NSi and H 2 SiN) in their electronic ground state using the standard coupled cluster approach (RCCSD(T)/augcc-pV5Z) and using the newly implemented explicitly correlated RCCSD(T)-F12a/b techniques. This work does not treat the trans-HSiNH form because of the multiconfigurational nature of its wavefunction in contrast to the monoconfigurational nature of two others.…”