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The effects of the introduction of argon atoms on the photoelectron (PE) spectra of Ar(sub n).(IHI)(super -) with n=0-6, 12, and 20 are investigated. Simulations show a shift of the spectra to lower electron kinetic energies as the number of argon atoms is increased, and an accumulation of transitions in the low-frequency hindered rotor region with increasing number of argon atoms is observed.

The vibrational and electronic absorption spectra of dibenzo[b,def]chrysene (DBC) and its ions in argon matrixes are recorded. It is observed that the electronic absorption bands of the DBC ions lie in close proximity to several of the diffuse interstellar visible absorption bands.

Infrared absorptions for the matrix-isolated lead and tin hydroxides M(OH), M(OH)2, and M(OH)4 (M = Pb, Sn) are observed in laser-ablated metal atom reactions with H2O2 during condensation in excess argon. The minimum energy structure found for M(OH)2 has Cs symmetry and a weak intramolecular hydrogen bond.

Infrared spectra of unstable species such as CO-free ruthenium tetraphenylporphyrin RuTPP and RuCOTPP isolated in solid argon at 8 K is recorded. Selective deposition conditions allow the isolation of either RuTPP and RuCOTPP or RuCOTPP and Ru(CO)2TPP.

The molecular structure, infrared spectrum and UV photochemistry of 2-methyl-2H-tetrazol-5-amine (2MTA) isolated in solid argon were investigated. The infrared spectrum of matrix-isolated 2MTA was fully assigned and correlated with structural properties.

The advances in argon predissociation spectroscopy to record the spectroscopic signature of the shared proton oscillations in the H(sub 3)O(sub 2)(super -) system were examined and the resulting spectrum with that of the H(sub 5)O(sub 2)(super +) ion taken under similar conditions is compared. Results revealed that very intense 1

Argon predissociation spectroscopy is used to observe the first vibrational spectra of the OH(super -).H2O and Cl(super -).H2O complexes in the 1000--1900 cm(super -1) energy region. The extension to lower energy allows the exploration of the spectral signatures of the intramolecular bending fundamentals (v2) of the bound water molecule, as well as, in the strongly bond systems such as OH(super -).H2O, the motion of the shared proton.

The vibrational spectroscopic and quantum chemical calculations of the (CS2)2(super -) anion produced by condensation of high-frequency discharged CS2 in excess neon and argon are reported. Photosensitive absorptions at 909.0 cm (super -1) in neon and 908.0 cm(super -1) in argon are assigned to the antisymmetric CS2 stretching vibrational mode (b(sub 2u) of the (CS2)2(super -) anion on the basis of isotopic substitution experiments.

In studies conducted ammonia and hydrogen vapors from the thermal decomposition of NH4I were codeposited with excess neon at 5 K to form the H3N-HI complex. Findings reveal that the matrix environment markedly affects the hydrogen bonding interaction and the degree of proton transfer in the polar H3N-HI hydrogen bonded complex.

Infrared photodissociation spectra of n-propylbenzene (n-PB)-Ar cluster cations are presented in the CH stretching vibrational region. Spectral analysis suggests that ionization of (n-PB)-Ar cluster cations show delocalization of positive charge of aromatic ring into the alkyl chain.

The simplest transition metal oxide cation, ScO(super +), trapped in solid noble gas matrixes, is coordinated by five noble gas atoms. The ScO(super +) ion observed in solid matrixes should be regarded as the [ScO-(Ng)5]( super +) complex.

Several studies are conducted to determine the mode spectrum of the thermal boundary resistance exhibited by two different bodies with a significant temperature difference. Several molecular dynamics simulations of the argon-like crystals are conducted to demonstrate the significance of the methodology.

The x-ray photoelectron spectroscopy technique is employed to analyze the surface current reduction observed in the (211) oriented [Cd.sub.0.46][Zn.sub.0.04][Te.sub.50] crystals by Ar bombardment. The Ar plasmas are shown to be extremely beneficial in changing the surface chemistry of the crystals.

Optical emission spectroscopy is used for studying a high pressure, slot-type, argon dc microdischarge, with added traces of nitrogen. The axial distribution of electron density as well as visual observation has shown that the microdischarge positive column is highly constricted and the electron density near the sheath edge has increased with both pressure and current.

Argon matrix ESR spectroscopy was used to characterize 3-isoquinolylnitrene together with a diradical species generated by photolysis of tetrazolo[1,5-b]isoquinoline/3-azidoisoquinoline. The results showed that the interconversion of azirenes occurs via the unobserved diazacycloheptatetraene/diazacycloheptatrienylidene while the rearrangement of azirene to ketenimine and 1-cyanoisoindole takes place via reversion to nitrene followed by ring opening to diradical.

Microwave cavity discharge in the supersonic flow of Ar/[H.sub.2][Air mixtures and its characterization based on the emission spectroscopy techniques are described. The effects seen with addition of [H.sub.2] into Ar plasma and with addition of air into Ar/[H.sub.2] plasma is discussed.

The study conducted obtains collision-induced emission spectra from 190-1020 nm for [N.sub.2.sup.+.]/Ar collisions at laboratory frame collision energies from 2 to 8 keV. Study result supports the curve-crossing mechanism for collisional activation.

The fifth harmonic at 162 nm, 11 fs that is generated in a short argon cell from 12 fs Ti-sapphire laser pulses is used to excite [C.sub.2][H.sub.4] and [C.sub.2][D.sub.4] in the maximum of the first [pi][pi]* transition. The vibrational data for both [C.sub.2][H.sub.4] and [C.sub.2][D.sub.4], in the Franck-Condon region and in the region before departure to the ground state are used for calibrating simulations of ultraviolet (UV) and other spectra.

The vibrational autodetachment (VAD) is compared as a spectroscopic method to vibrational Ar predissociation for nitroalkane anions up to nitropentane. The low electron-binding energy has facilitated VAD as well as direct photodetachment in the energy region of the CH stretching fundamentals with overtones and combination bands of HCH bending modes.

The zero electron kinetic energy and mass analyzed threshold ionization spectroscopy technique is employed to determine the cation vibronic spectra and the binding energy of the 1,4-benzodioxan-[Ar.sub.1] and -[Ar.sub.2] complexes. All the Ar atoms present in the complexes are shown to exhibit similar binding geometry.

N-Heterocyclic carbenes (NHCs) are used as catalysts for the reaction of N-tosylimines with aziridines and electron-deficient unsaturated compounds. The results have shown that N-tosylimine-NHC adduct is an active species.

The Ar-Xe infrared laser is examined in the Naval Research Laboratory's Electra generator in order to optimize the efficiency of the laser. The incomplete picture of Ar-Xe laser physics is traceable in large part to significant uncertainties still present in many important rates influencing the atomic and molecular kinetics.

A self-consistent theoretical model was developed to study the spatial structure of a large-scale, slot-antenna excited surface wave plasma source operating in [N.sub.2]-Ar mixtures. The results obtained suggested that the processes of excited species production in the remote plasma zone of the microwave source could be controlled by changing the mixture composition and the dissociation degree of [N.sub.2] molecules.

The Rayleigh scattering technique is employed to demonstrate the presence of the argon clusters formed in a planar expansion. The mean cluster size of argon is shown to be highly dependent on the stagnation pressure.

The electron-scattering cross sections and optical data for the argon atom are described. The progress made in the field of electron scattering and photoabsorption and the appropriate criteria for verifying data consistency are discussed.

The infrared photodissociation spectra and ab initio calculations for protonated carbon dioxide clusters and its complexes with argon are reported. The monomers and dimmers have a nonlinear configurations but in the trimer the core C[O.sub.2] dimer ion undergoes structural rearrangement to a boat structure which remains unaffected upon further C[O.sub.2] solvation. The addition of argon leads to an uneven sharing of protons but does not affect the asymmetric C[O.sub.2] stretch vibrations.

The reactions of laser-ablated germanium atoms with water molecules in excess argon which have was studied by using matrix-isolation infrared specroscopy is presented.

Mode transitions and hysteresis in inductively coupled plasma in Ar and Ar/[N.sub.2] mixtures were examined by optical emission spectroscopy as a noninvasive plasma diagnostic. Small changes of the electron energy distribution function in the region of the mode transition were observed along with enhanced production of metastables in the hysteresis region.

The photochemistry of 3-iodo-2,4,5,6-tetrafluorophenyl azide and 3,5-diiodo-2,4,6-trifluorophenyl azide are studied by IR and EPR spectroscopy in cryogenic argon and neon matrices. The results indicate strong through-bond coupling of exocyclic orbital in metal position with the singly occupied in-plane nitrene orbital in the monoradical nitrenes.

Reactions of laser-ablated tin and lead atoms with nitric oxide molecules in solid argon and neon are investigated using matrix-isolation infrared spectroscopy. Infrared spectroscopy coupled with theoretical calculations present evidence for the formation of M(NO.sub.n) (M= Sn, Pb; n = 1,2) and [PbNO.sup.-] molecules.

The vibrational spectra of Ag3 and Ag4 are recorded in the far-infrared (FIR) region by using multiple photon dissociation spectroscopy of their complexes with Ar atoms. The results have shown that the influence of the number of Ar atoms in the complexes on the frequency of the IR active modes is very minor.

The densities of NH and NH2 radicals in an Ar-NH3 plasma jet created by the expanding thermal plasma source are examined for various source-operating condition such as plasma current and NH3 flow. The key production reactions of NH and NH3 are discussed from the combination of the data with ion density and NH3 consumption measurements in the plasma as well as from a simple one-dimensional plug down model.

The plasma chemistry of NO is investigated in gas mixtures with oxygen and hydrocarbon and Ar as carrier gas by using surface wave discharges operating at microwave frequencies. The results obtained provide interesting insights about the plasma removal of NO in real gas exhausts.

A systematic study of the microstructural evolution of Si-rich SiO(sub x) films, after ion irradiation and postirradiation heat treatment is carried out by means of vibrational spectroscopy techniques. Si-rich silicon oxide films are proposed on c-Si (100) wafers by a rf (13.56 MHz) plasma-enhanced chemical vapor deposition apparatus from SiH4 and N2O gas mixtures under different flow ratios N2O/SiH4.

The role of the dissociative recombination in argon microwave plasma with a collisional radiative model is studied. The results show that dissociative recombination principally populates the ground state and the 4s levels.

The aim of the study is to make a reliable assignment of the vibrational modes in the Fourier-transform infrared (FTIR) spectra of 5-halouracils trapped in low-temperature Ar matrixes. The infrared low-temperature Ar-matrix spectra of 5-halouracils and unsubstituted uracil are measured and interpreted in terms of the spectra calculated at the DFT/B3PW91/6-311G** level followed by a potential energy distribution (PED) analysis.

The change in electron density is investigated using the plasma frequency by the wave cutoff method and the behavior of ion species with a quadrupole mass spectrometer (QMS) in pure Ar and O2 and mixed O2/Ar plasmas. It is found that the electron density in both pure Ar and O2 plasma increases with rf power, because higher rf power has a higher ionization effect, which contributes more electrons to plasma.

The argon predissociation spectra of the Cl2(super -1).nH2O (n=1-5) clusters in OH stretching region is reported. The spectra of the mono- and dihydrates consist of only a single sharp feature, indicating that the water molecules bind symmetrically to the ion in both cases.

Resonant-enhanced multiphoton ionization (REMPI) and mass-analyzed threshold ionization (MATI) spectra of 2-aminopyridine (2AP-NH2).Arn clusters are presented to give the S1-S0 spectral origins of 33 439 and 33 411 cm to the power -1 for the 2AP-NH2.Ar and 2AP-NH2.Ar2 clusters, respectively, and also their respective adiabatics ionization energies of 8.0881+_0.0021 and 8.0676 +_ 0.0020 eV. Ab initio calculated cluster structures are also provided.

The synthesis and characterization of the molecular species Ar'CdCdAr' (Ar' = [C.sub.6][H.sub.3]-2,6-[([C.sub.6][H.sub.3]-2,6-[Pr.sub.2.sup.1]).sub.2]) is described and shown that it possesses considerable thermal stability. The density functional theory (DFT) calculations have shown that Ar'CdCdAr' has significant p-character in the Cd-Cd bonding orbital.