Electronic structure calculations as a tool in the quest for experimental verification of N4

The dissociation energy for decomposition of N 4 ( T d )( 1 ) into two N 2 molecules is 182 kcal/mol at 0 K according to the latest calculations. Despite this large energy difference the activation energy for the spin-allowed dissociation process is close to 60 kcal/mol. New calculations, presented in this chapter for the first time, indicate that the effective barrier due to intersystem crossing with the triplet state is close to 51 kcal/mol. This indicates that 1 is more stable than previously believed and would be an excellent high energy density material (HEDM) if synthesized. The other singlet state N 4 isomer, N 4 ( D 2h ) ( 3 ), is very similar in energy to 1 . However, the dissociation barrier is only 7 kcal/mol at 0 K according to high level calculations. Thus, 3 is not a realistic candidate for a HEDM.

[1]  R. Bartlett,et al.  The 28-Electron Tetraatomic Molecules: N4, CN2O, BFN2, C2O2, B2F2, CBFO, C2FN, and BNO2. Challenges for Computational and Experimental Chemistry , 1996 .

[2]  Julia E. Rice,et al.  Theoretical characterization of tetrahedral N4 , 1991 .

[3]  M. Jacox,et al.  The vibrational spectra of molecular ions isolated in solid neon. III. N+4 , 1990 .

[4]  John F. Stanton,et al.  The equation of motion coupled‐cluster method. A systematic biorthogonal approach to molecular excitation energies, transition probabilities, and excited state properties , 1993 .

[5]  P. Schleyer,et al.  The N4 molecule has an open-chain triplet C2h structure , 1993 .

[6]  Keiji Morokuma,et al.  TRANSITION STATE FOR THE DISSOCIATION OF TETRAHEDRAL N4 , 1995 .

[7]  T. Brinck,et al.  Ab initio study of the ground state and the first excited state of the rectangular (D2h) N4 molecule , 2001 .

[8]  T. Venanzi,et al.  The N4 molecule and the N3 + ion , 1975 .

[9]  P. Schleyer,et al.  Besides N(2), What Is the Most Stable Molecule Composed Only of Nitrogen Atoms? , 1996, Inorganic chemistry.

[10]  T. Brinck,et al.  A theoretical study of the azide (N3) doublet states. A new route to tetraazatetrahedrane (N4): N+N3→N4 , 2002 .

[11]  Ashwani Vij,et al.  Experimental detection of the pentaazacyclopentadienide (pentazolate) anion, cyclo-N5-**. , 2002, Angewandte Chemie.

[12]  Edward Teller,et al.  Electronic Spectra of Polyatomic Molecules , 1941 .

[13]  J. G. Radziszewski,et al.  Tetrazete (N4). Can it be prepared and observed , 2000 .

[14]  Christopher E. Dateo,et al.  Towards the synthesis of the high energy density material TdN4: excited electronic states , 2001 .

[15]  R. Bartlett,et al.  Coupled-cluster calculations of Raman intensities and their application to N4 and N5− , 1999 .

[16]  P. Jørgensen,et al.  Frequency-dependent first hyperpolarizabilities using coupled cluster quadratic response theory , 1997 .

[17]  F. Negri,et al.  N6.bul.-. Spectroscopic and Theoretical Studies of an Unusual Pseudohalogen Radical Anion , 1995 .

[18]  D. Yarkony.  Theoretical studies of spin-forbidden radiationless decay in polyatomic systems : insights from recently developed computational methods , 1992 .

[19]  A. E. Lewis,et al.  Vacuum ultraviolet photoelectron spectroscopy of transient species: Part 15. The N3(X2II) radical , 1982 .

[20]  T. Brinck,et al.  Theoretical study of the triplet N-4 potential energy surface , 2000 .

[21]  P. Bernath,et al.  Fourier transform spectroscopy of the ν3 band of the N3 radical , 1988 .

[22]  G. de Petris,et al.  Experimental Detection of Tetranitrogen , 2002, Science.

[23]  Timothy J. Lee,et al.  An accurate quartic force field, fundamental frequencies, and binding energy for the high energy density material TdN4 , 2002 .

[24]  J. Facelli,et al.  Vibrational and electronic spectra of matrix-isolated nitrogen trimer radical and azide , 1988 .

[25]  W. Jones,et al.  THE 2 700 A BANDS OF THE N3 MOLECULE , 1965 .

[26]  John F. Stanton,et al.  Stability and energetics of metastable molecules: tetraazatetrahedrane (N4), hexaazabenzene (N6), and octaazacubane (N8) , 1992 .

[27]  Theodor Curtius.  Ueber Stickstoffwasserstoffsäure (Azoimid) N3H , 1890 .

[28]  J. Wasilewski.  Stationary points on the lowest doublet and quartet hypersurfaces of the N3 radical: A comparison of molecular orbital and density functional approaches , 1996 .

[29]  K. Christe,et al.  Polynitrogen chemistry. Synthesis, characterization, and crystal structure of surprisingly stable fluoroantimonate salts of N5+. , 2001, Journal of the American Chemical Society.

[30]  S. Nizkorodov,et al.  A 3.PI.u .rarw. X 3.SIGMA.g- Electronic Spectrum of N3+ , 1994 .