The visible absorption spectrum of OBrO, investigated by Fourier transform spectroscopy

By the utilization of a new laboratory method to synthesize OBrO employing an electric discharge, the visible absorption spectrum of gaseous OBrO has been investigated. Absorption spectra of OBrO have been recorded at 298 K, using a continuous-scan Fourier transform spectrometer at a spectral resolution of 0.8 cm(-1). A detailed vibrational and rotational analysis of the observed transitions has been carried out. The FTS measurements provide experimental evidence that the visible absorption spectrum of OBrO results from the electronic transition C(2A2)-X(2B1). Vibrational constants have been determined for the C(2A2) state (omega(1) = 648.3 +/- 1.9 cm(-1) and omega 2 = 212.8 +/- 1.2 cm(-1)) and for the X(2B1) state (omega 1 = 804.1 +/- 0.8 cm(-1) and omega 2 = 312.2 +/- 0.5 cm(-1)). The vibrational bands (1,0,0), (2,0,0), and (1,1,0) show rotational structure, whereas the other observed bands are unstructured because of strong predissociation. Rotational constants have been determined experimentally for the upper electronic state C(2A2). By modeling the band contours, predissociation lifetimes have been estimated. Further, an estimate for the absorption cross-section of OBrO has been made by assessing the bromine budget within the gas mixture, and atmospheric lifetimes of OBrO have been calculated using a photochemical model.     

Crystallization and Preliminary Crystallographic Studies of Cucurmosin 2,a Ribosome-inactivating Protein from the Sarcocarp of Cucurbita moschata

Cucurmosin 2, a type 1 ribosome-inactivating protein （RIP） isolated from sarcocarp of Cucurbita moschata, has been crystallized by the vapor-diffusion method using PEG6000 as the precipitant. The crystals belong to the orthorhombic space group P212121, with unit cell parameters a = 55.853, b = 65.507, c = 91.754 А, and have one molecule per asymmetric unit. X-ray data have been collected to 1.8А, using a synchrotron source.     

High-resolution spectroscopic investigation of the ~B2A1-- ~X2A1 transitions of CaCH3 and SrCH3

High-resolution spectra of the ~B(2)A(1)-- ~X(2)A(1) transitions of CaCH(3) and SrCH(3) have been recorded in a molecular jet/laser ablation source using laser excitation spectroscopy. Transitions arising from the K = 0 and 1 sub-bands have been observed for both molecules. An analysis of the data using a (2)A(1) symmetric top Hamiltonian has determined rotational and spin-rotation constants for the ~B(2)A(1) state of each molecule. From the rotational constants, structures have been estimated for both CaCH(3) and SrCH(3). The spin-rotation constant, epsilon(bc) = (epsilon(bb) + epsilon(cc))/2, in the ~B(2)A(1) state for both molecules is in reasonable agreement with the value calculated using the pure precession approximation. For CaCH(3), the K' = 1 levels of the ~B(2)A(1) state exhibit a perturbation that interchanges the energy ordering of the spin-rotation components.     

Observation of the 71Pig state of Na2 by optical-optical double resonance spectroscopy

The 71Pig Rydberg state of Na2 correlating with the separated atom limit Na(3s) + Na(5p) has been observed using high-resolution cw optical-optical double resonance spectroscopy. A total of 104 identified rovibrational levels in the range v = 0-12 and 11 相似文献   

The NaK 1 1,3delta states: theoretical and experimental studies of fine and hyperfine structure of rovibrational levels near the dissociation limit

Earlier high-resolution spectroscopic studies of the fine and hyperfine structure of rovibrational levels of the 1 3delta state of NaK have been extended to include high lying rovibrational levels with v < or = 59, of which the highest levels lie within approximately 4 cm(-1) of the dissociation limit. A potential curve is determined using the inverted perturbation approximation method that reproduces these levels to an accuracy of approximately 0.026 cm(-1). For the largest values of v, the outer turning points occur near R approximately 12.7 angstroms, which is sufficiently large to permit the estimation of the C6 coefficient for this state. The fine and hyperfine structure of the 1 3delta rovibrational levels has been fit using the matrix diagonalization method that has been applied to other states of NaK, leading to values of the spin-orbit coupling constant A(v) and the Fermi contact constant b(F). New values determined for v < or = 33 are consistent with values determined by a simpler method and reported earlier. The measured fine and hyperfine structure for v in the range 44 < or = v < or = 49 exhibits anomalous behavior whose origin is believed to be the mixing between the 1 3delta and 1 1delta states. The matrix diagonalization method has been extended to treat this interaction, and the results provide an accurate representation of the complicated patterns that arise. The analysis leads to accurate values for A(v) and b(F) for all values of v < or = 49. For higher v (50 < or = v < or = 59), several rovibrational levels have been assigned, but the pattern of fine and hyperfine structure is difficult to interpret. Some of the observed features may arise from effects not included in the current model.     

Synthesis,crystal structure,and magnetic properties of an alkoxo-hydroxo-bridged octanuclear copper(II) complex showing chemically significant hydrogen-bonding interactions involving a metallamacrocyclic core

A novel 16-member metallamacrocyclic octanuclear copper(II) complex of formulation [Cu8L4(OH)4] (1) has been prepared from a reaction of [Cu2L(O2CMe)] and NaOH in methanol, where L is a pentadentate trianionic Schiff base ligand N,N'-(2-hydroxypropane-1,3-diyl)bis(salicylaldimine). The complex has been characterized by analytical, structural, and spectral methods. It crystallizes in the monoclinic space group C2/c with the following unit cell dimensions: a = 30.365(3) A; b = 14.320(2) A; c = 19.019(2) A; beta = 125.33(2) degrees; V = 6746.7(13) A3; Z = 4. A total of 4589 unique data with l > 2 sigma (l) were used to refine the structure to R1(F0) = 0.0525 and wR2 = 0.1156. The structure consists of four binuclear [Cu2L]+ units linked covalently by four hydroxide ligands to form an octanuclear core which is stabilized by strong hydrogen-bonding interactions involving the hydroxide ligands. Each binuclear unit has a pentadentate ligand L showing N2O3 coordination with an endogenous alkoxide bridging atom. The magnetic susceptibility data of 1, obtained in the temperature range 14-306 K, show the presence of antiferromagnetic exchange interactions between adjacent spin-1/2 Cu(II) ions. The mu eff values are 1.54 and 0.26 microB (per copper) at 295 and 15 K, respectively. The magnetic data have been theoretically fitted using a Heisenberg spin-1/2 Hamiltonian with nearest-neighbor antiferromagnetic interactions. The spin coupling in the metallamacrocyclic ring has been modeled using four different coupling constants (J) on the basis of the structural parameters of the octanuclear core. The coupling constants obtained are J1 = -318.8, J2 = -293.3, J3 = -111.6, and J4 = -63.8 cm-1. The theoretical modeling of the susceptibility data gives a higher magnitude of the antiferromagnetic interaction within the binuclear [Cu2L]+ unit compared to those involving adjacent dimeric units.     

Synthesis and characterization of a new three-dimensional lanthanide carboxyphosphonate: Ln(4)(H(2)O)(7)[O(2)C-C(5)H(10)N-CH(2)(-)PO(3)](4)(H(2)O)(5)

The first open-framework lanthanide carboxyphosphonate has been obtained under hydrothermal conditions. The three-dimensional structure of MIL-84(Pr) (MIL = Material Institut Lavoisier) or Pr(4)(H(2)O)(7)[O(2)C-C(5)H(10)N-CH(2)(-)PO(3)](4)(H(2)O)(5) has been solved from X-ray diffraction single-crystal data (a = 23.481(1) A, b = 10.159(1) A, c = 23.006(1) A, beta = 105.63(1) degrees, V = 5284.6(6) A(3), space group Cc (No. 9)). Its framework is built up from chains of edged-sharing eight or nine-coordinated monocapped square antiprism polyhedra and carboxyphosphonate anions, creating a three-dimensional structure with small pores filled with water molecules. The thermal behavior of MIL-84(Pr) has been investigated using TGA and X-ray thermodiffractometry and indicates that MIL-84(Pr) is stable up to 523 K with a reversible hydration-dehydration process. The optical study of its yttrium analogue doped at 3.4% with europium (MIL-84(Y,Eu)) reveals a significant red-orange emission under UV radiation.     

Parametrization of the magnetic behavior of the triangular spin ladder chains organically templated: (C2N2H10)[M(HPO3)F3] (M(III) = Fe, Cr, and V). Crystal structure and thermal and spectroscopic properties of the iron(III) phase

A new iron(III) phosphite templated by ethylenediamine has been synthesized using solvothermal conditions under autogenous pressure. The (C2N2H10)[Fe(HPO3)F3] compound has been characterized by single-crystal X-ray diffraction data and spectroscopic and magnetic techniques. The crystal structure is formed by chains extended along the c axis and surrounded by ethylenediammonium cations. A study by diffuse-reflectance spectroscopy has been performed, and the calculated Dq, B, and C parameters for the Fe(III) cations are 1030, 720, and 3080 cm(-1), respectively. The M?ssbauer spectrum at room temperature is characteristic of Fe(III) ions. The electron spin resonance (ESR) spectra carried out at different temperatures show isotropic signals with a g value of 2.00(1). The thermal evolution of the intensity of the ESR signals indicates the existence of antiferromagnetic interactions for the Fe(III) phase. The magnetic susceptibility data of the Cr(III) and V(III) compounds show antiferromagnetic couplings. The J-exchange parameters of the Fe(III) and Cr(III) compounds have been calculated by using a model for a triangular spin ladder chain. The values are J1 = -1.63(1) K and J2 = -0.87(2) K with g = 2.02 for the Fe(III) phase and J(1) = -0.56(2) K and J2 = -0.40(2) K with g = 1.99 for the Cr(III) compound. In the case of the V(III) phase, the fit has been performed considering a linear chain with the magnetic parameters D = 2.5 cm(-1) and J = -1.15(1) K.     

Elementary swelling and gelling theories

It has been experimentally illustrated that it is possible to form an n-phase thermodynamic system where n> or =2 and has a value which is limited by the properties of the system. For example, to attain limited chemical reversibility of a mineral matrix such as vermiculite using specific butyl ammonium vermiculite, it is necessary to reform chemical bonds using an additive and a particular ion. In other words, to obtain a similar thin film using exfoliated vermiculite as that obtained with natural vermiculite, hydrophobic or binding electrostatic bonds must be formed or reformed. It has also been observed that complementary structural compounds can be formed from other silicates, such as glycerine/sodium silicate. These compounds can also encase the vermiculite matrices. (Film Formation) is proportional to (A/Temp). (Pressure).(Ionic Content). Hence F=L(A/T)PE, where F=film formation, L=functional constant for the matrix compound, T=temperature, A=temperature constant, P=pressure, E=electrostatic force and P=force/area. Thus, F=LTE2 for unit area. SigmaF=pfL. TE2/SigmaPefl=F1, where P=the probability for film formation and SigmaPef(L) is the partition function for the film formation. This concept can be extended to a response geometric algorithm. This means that for every mineral matrix there is an algorithm to describe its formation or its response to an applied field. Thus deltasec2(E)tan(E1) is the response for (F1). V---, V1...Vn, F1...Fn1, ..., Fp, ...Fnp.     

Theoretical study of potential energy surface and vibrational spectra of ArF2 system

An ab initio potential energy surface (PES) of ArF2 system has been obtained by using MP4 calculation with a large basis set including bond functions. There are two local minimums on the PES: one is T-shaped and the other is L-shaped. The L-shaped minimum is the global minimum with a well depth of -119.62 cm- 1 at R = 0.3883nm. The T-shaped minimum has a well depth of -85.93cm -1 at R = 0.3486 nm. A saddle point is found at R = 0.3486 and θ = 61° with the well depth of -61.53 cm-1. The vibrational energy levels have been calculated by using VSCF-CI method. The results show that this PES supports 27 vibrational bound states, and the ground states are two degenerate states assigned to the L-type vibration.     

Structure Prediction Based on Hydrophobic to Hydrophilic Volume Ratios in Small Molecule Amphiphilic Organic Crystals

<正>The structure type for the crystal of 4,4'-bis-(2-hydroxy-ethoxyl)-biphenyl 1 has been predicted by using the previously developed interfacial model for small organic molecules. Based on the calculated hydrophobic to hydrophilic volume of 1, this model predicts the crystal structure to be of lamellar or bicontinuous type, which has been confirmed by the X-ray single-crystal structure analysis (C20H26O6, monoclinic, P21/C, a = 16.084(1), b = 6.0103(4), c = 9.6410(7) A, β9 = 103.014(2)°, V= 908.1(1) A3, Z = 2, Dc= 1.325 g/cm3, F(000)=388,μ = 0.097 mm-1, MoKα radiation, λ = 0.71073 A, R = 0.0382 and wR = 0.0882 with I > 2σ(I) for 7121 reflections collected, 1852 unique reflections and 170 parameters). As predicted, the hydrophobic and hydrophilic portions of 1 form in the lamellae. The same interfacial model is applied to other amphilphilic small molecule organic systems for structural type prediction.     

Paired hydrogen bonds in the hydrogen halide homodimer (HI)2

The HI homodimer was found to have structural and vibrational properties unlike any other previously studied (HX)(2) system, with X = F, Cl, and Br. The infrared spectrum of (HI)(2) is also observed to be distinctly different from the other members of the series. In addition, the interaction energy of the (HI)(2) dimer has been calculated using the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory. A four-dimensional morphed intermolecular potential has been generated and then morphed using available near infrared and submillimeter spectroscopic data recorded in supersonic jet expansions. The morphed potential is found to have a single global minimum with a symmetric structure having C(2h) symmetry. The equilibrium dissociation energy is found to be 359 cm(-1) with the geometry in Jacobi coordinates of R(e) = 4.35 A?, θ(1) = 43°, θ(2) = 137°, and φ = 180°. The infrared spectrum is characterized by pairs of excited vibrational states resulting from the coupling of the two HI stretching modes. A qualitative model using a quadratic approximation has been fitted to obtain an estimate of this coupling. Furthermore, a morphed intermolecular potential for the vibrationally excited system was also obtained that gives a quantitative estimate of the shift in the potential due to the excitation. The submillimeter analysis is consistent with a ground state having its highest probability as a paired hydrogen bond configuration with R(0) = 4.56372(1) A? and an average angle θ=cos(-1)((1/2)) = 46.40(1)° (between the diatom center of mass∕center of mass axis and direction of each component hydrogen iodide molecule). On monodeuteration, however, the ground state is predicted to undergo an anomalous structural isotope change to an L-shaped HI-DI structure with highest probability at R(0) = 4.51 A?, θ(1) = 83°, θ(2) = 177°, and φ = 180°. These results provide a test for large scale ab initio calculations and have implications for the interpretation of photoinduced chemistry and other properties of the dimer.     

Ni(III) complex of an N-confused porphyrin inner C-oxide

A novel, structurally characterized Ni(III) complex of an N-confused porphyrin inner C-oxide has been synthesized from the oxidation of a Ni(II) N-confused porphyrin using OsO4. Crystal data: C53H40N5NiO.CH2Cl2, monoclinic, space group P2/a (No. 13), a=21.229(1) A, b=8.6451(5) A, c=25.762(2) A, beta=93.004(3) degrees, V=4721.6(5) A3, and Z=4.     

Density functional theory study on the structure and vibrational frequencies of glycylglycine

Eleven possible conformers of glycylglycine have been studied by using the BLYP, B3LYP methods of density functional theory and the HF method at the basis set of 6-311++G**. BLYP (using Becke's and Lee-Yang-Parr's correlation functionals), ab initio Hartree-Fock (HF) and hybrid DFT/HF B3LYP calculations have been carried out to study the structure and vibrational spectra of glycylglycine. Glycylglycine crystal structure has been determined by X-ray diffraction analysis. The title compound has been crystallizes in the orthorhombic space group C1, with Z=4. And the unit cell parameters are: a=8.1184(12)A, b=9.5542(14)A, c=7.8192(11)A and V=577.95(15)A(3). Molecular conformation calculations have got 11 possible conformers. In these possible conformers, the most stable one has been selected. The BLYP/6-311++G** and scaled HF/6-311++G** frequencies correspond well with available experimental assignments of the normal vibrational modes. Comparison of the observed fundamental vibrational frequencies of glycylglycine and calculated results by density functional B3LYP and Hartree-Fock (HF) methods indicates that B3LYP is superior to the scaled Hartree-Fock (HF) for molecular vibrational issues.     

Development of a low volume plasma sample precipitation procedure for liquid chromatography/tandem mass spectrometry assays used for drug discovery applications

The demand for high sensitivity bioanalytical methods has dramatically increased in the drug discovery stage; in addition, there has been a growing trend of reducing the sample volume that is required for these assays. A sensitive high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) procedure has been developed and tested to meet these needs. The assay requires only a low plasma sample volume (10 microL) and employs a protein precipitation procedure using a 1:6 plasma/acetonitrile ratio. The supernatant is injected directly into the LC/MS/MS system using the selected reaction monitoring (SRM) procedure for detection. A generic HPLC gradient based on a methanol/water mobile phase with a flow rate set to 0.8 mL/min was used. The test method showed very good linearity between 0.1-1000 ng/mL (R2 = 0.9737), precision (%RSD = 6-9), accuracy (%RE = -2) and reproducibility (%RSD = 11). A drug discovery IV/PO study was assayed using both the new low volume method and our standard volume (50 microL) method. The correlation of the two sets of data from the two methods was excellent (R2 = 0.9287). This new assay procedure has been successfully used in our laboratory for over 100 different rat or mouse discovery PK studies.     

Theoretical studies of molecular structure and vibrational spectra of O-ethyl benzoylthiocarbamate

O-Ethyl benzoylthiocarbamate has been synthesized and characterized by elemental analysis and FT-IR. The crystal structure was determined by X-ray diffraction analysis. Title compound crystallizes in the orthorhombic space group Pna2(1), with Z=4. Unit cell parameters a=9.941(3)A, b=9.352(3)A, c=10.962(3)A and V=1019.1(5)A(3). The molecular geometry and vibrational frequencies of O-ethyl benzoylthiocarbamate in the ground state has been calculated using the Hartree-Fock and density functional using Becke's three-parameter hybrid method with the Lee, Yang, and Parr correlation functional (B3LYP) methods with 3-21G and 6-31G(d) basis sets. The computational frequencies are in good agreement with the observed results. Comparison of the observed fundamental vibrational frequencies of O-ethyl benzoylthiocarbamate and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems.     

Two-photon absorption of photochromic diarylethene and its application to rewritable holographic recording

A new photochromic diarylethene (1a) has been prepared. Both its photochromic behavior and nonlinear optical properties are investigated. 1a shows excellent ring-opening (λ_max = 386 nm) and ring-closing (λ_max = 652 nm) photoisomerization with UV-Vis light irradiation. With 800 nm femtosecond pulsed laser irradiation, 1a shows two-photon-induced photoisomerization, and a two-photon absorption cross-section (σ = 423×10⁵⁰ cm⁴·s per photon) is obtained by using two-photon induced fluorescence method. The applications of two-photon absorption of 1a to holographic recording has been also investigated. A two-photon induced micro-pattern is recorded on the diarylethene 1a-PMMA film with an femtosecond laser of 800 nm, 100 fs, 1 kHz, 50 mW.     

Blue-luminescent/electroluminescent Zn(II) compounds of 7-azaindole and N-(2-pyridyl)-7-azaindole: Zn(7-azaindole)2(CH3COO)2, Zn(NPA)(CH3COO)2, and Zn(NPA)((S)-(+)-CH3CH2CH(CH3)COO)2 (NPA = N-(2-pyridyl)-7-azaindole)

A new 7-azaindole zinc(II) compound, Zn(7-azaindole)2(CH3COO)2 (1), a new ligand N-(2-pyridyl)-7-azaindole (NPA), and two NPA zinc(II) complexes, Zn(NPA)(CH3COO)2 (2) and Zn(NPA)((S)-(+)-CH3CH2CH(CH3)COO)2 (3), have been synthesized and structurally characterized. Compound 1 has a tetrahedral geometry, whereas compounds 2 and 3 have irregular six-coordinate geometry. The NPA ligand in compounds 2 and 3 functions as a bidentate chelate to the zinc center. Compound 1 has a blue luminescence in the solution and the solid state. Compounds 2 and 3 emit a blue color in the solid state. In solution, compounds 2 and 3 are fluxional, as established by 1H NMR experiments. Compound 1 is thermally stable, whereas compounds 2 and 3 undergo decomposition when heated in the solid state. A blue electroluminescent device using compound 1 as the emitting layer has been fabricated. Crystal data: NPA, monoclinic, P2(1)/c, a = 13.993(5) A, b = 8.456(3) A, c = 16.886(5) A, beta = 104.666(12) degrees, V = 1932.9(11) A3; 1, triclinic, P1, a = 9.5114(18) A, b = 10.460(7) A, c = 11.002(3) A, alpha = 117.18(3) degrees, beta = 103.287(18) degrees, gamma = 90.94(2) degrees, V = 938.3(7) A3; 2, monoclinic, C2/c, a = 13.234(6) A, b = 9.373(3) A, c = 13.956(7) A, beta = 113.24(3) degrees, V = 1590.7(12) A3; 3, monoclinic, P2(1), a = 11.047(7) A, b = 15.343(9) A, c = 13.785(8) A, beta = 100.123(9) degrees, V = 2300(2) A3.     

Syntheses,structural analyses,and magneto-structural correlations of three polymeric Fe(II) complexes with azide ligand

Three new metal-organic polymeric complexes, [Fe(N(3))(2)(bpp)(2)] (1), [Fe(N(3))(2)(bpe)] (2), and [Fe(N(3))(2)(phen)] (3) [bpp = (1,3-bis(4-pyridyl)-propane), bpe = (1,2-bis(4-pyridyl)-ethane), phen = 1,10-phenanthroline], have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature magnetic measurements in the range 300-2 K. Complexes 1 and 2 crystallize in the monoclinic system, space group C2/c, with the following cell parameters: a = 19.355(4) A, b = 7.076(2) A, c = 22.549(4) A, beta = 119.50(3) degrees, Z = 4, and a = 10.007(14) A, b = 13.789(18) A, c = 10.377(14) A, beta = 103.50(1) degrees, Z = 4, respectively. Complex 3 crystallizes in the triclinic system, space group P(-)1, with a = 7.155(12) A, b = 10.066(14) A, c = 10.508(14) A, alpha = 109.57(1) degrees, beta = 104.57(1) degrees, gamma = 105.10(1) degrees, and Z = 2. All coordination polymers exhibit octahedral Fe(II) nodes. The structural determination of 1 reveals a parallel interpenetrated structure of 2D layers of (4,4) topology, formed by Fe(II) nodes linked through bpp ligands, while mono-coordinated azide anions are pendant from the corrugated sheet. Complex 2 has a 2D arrangement constructed through 1D double end-to-end azide bridged iron(II) chains interconnected through bpe ligands. Complex 3 shows a polymeric arrangement where the metal ions are interlinked through pairs of end-on and end-to-end azide ligands exhibiting a zigzag arrangement of metals (Fe-Fe-Fe angle of 111.18 degrees) and an intermetallic separation of 3.347 A (through the EO azide) and of 5.229 A (EE azide). Variable-temperature magnetic susceptibility data suggest that there is no magnetic interaction between the metal centers in 1, whereas in 2 there is an antiferromagnetic interaction through the end-to-end azide bridge. Complex 3 shows ferro- as well as anti-ferromagnetic interactions between the metal centers generated through the alternating end-on and end-to-end azide bridges. Complex 1 has been modeled using the D parameter (considering distorted octahedral Fe(II) geometry and with any possible J value equal to zero) and complex 2 has been modeled as a one-dimensional system with classical and/or quantum spin where we have used two possible full diagonalization processes: without and with the D parameter, considering the important distortions of the Fe(II) ions. For complex 3, the alternating coupling model impedes a mathematical solution for the modeling as classical spins. With quantum spin, the modeling has been made as in 2.     

A3Pi1u<--X1Sigmag+ laser photoacoustic spectroscopy of Br2 vapor in the extreme red wavelength region 665-720 nm

The A3Pi1u<--X1Sigmag+ photoacoustic spectrum of Br2 vapor has been studied and vibronic analysis performed using earlier data available for this system of bands from optical spectroscopy in the region 665-720 nm. The vibronic levels involved in these transitions are 4< or =v'< or =21 and 1< or =v'< or =4. The relative photoacoustic intensities of the vibronic bands have been used in estimating the non-radiative relaxation rate from vibrational levels of A3Pi(1u) state. The non-radiative relaxation is found to be a nonlinear function of the upper state vibrational quantum number. The radiative rate constants for the A3Pi(1u) state vibrational levels have been compared with the corresponding non-radiative constants obtained from present work. Non-radiative decay rate constants for the vibrational levels of A3Pi(1u) state have been experimentally determined for the first time from photoacoustic spectrum of Br2 vapor in the extreme red region.