Rotational spectrum and spectroscopic constants of the phosphine molecule in the ground vibrational state

A comprehensive investigation of both the allowed and the forbidden rotational spectra of the phosphine molecule, PH₃, in the ground vibrational state is described. The new experimental microwave investigation covers the frequency region from 300 to 1070 GHz.     

Submillimeter spectrum and spectroscopic constants of the arsine molecule in the ground vibrational state

The submillimeter spectrum of the arsine molecule, AsH₃, of both the allowed R-branch transitions (J + 1 ← J, J = 0, 1, 2, 3) and forbidden transitions of the Q branches, |K| = 4 ← 7, 5 ← 8, 6 ← 9, is investigated in the frequency range from 220 to 900 GHz. Weak absorption lines were observed by using the spectrometer RAD with sensitivity increased by a nontunable cavity cell. On the basis of the results obtained and microwave data available in the literature the rotational spectrum of the arsine molecule in the ground state is analyzed.     

Bound state vibrational spectrum of the 3–9 atom-surface interaction

The potential $\text{V(z) =}\text{C}{}_9\text{z}{}^9\text{?}\text{C}{}_3\text{z}{}^3$ is a reasonable parametrization of the atom-surface interaction. We evaluate the discrete spectrum E_n of bound states for this potential with arbitrary coefficients C₉ and C₃. The resulting form in the WKB approximation is $\text{E}{}_{\mathrm{n}}\text{= ?D [1 ?}\text{(n +}\text{l}\text{2}\text{)}\text{L}\text{]}{}^6$, where L depends on the mass and D is the well depth. We find that the exact solution of the Schrödinger equation can be written in the same form, with n shifted slightly by an amount δ_n, which we calculate. The results are applied to the case of He near a NaF surface, in which the calculated eigenvalue spectrum agrees well with experimental values.     

Modeling of the vibrational structure of the vibronic spectrum and an excited state of the dinaphthylethylene molecule

The vibrational structure of the fluorescence spectrum and the structure of a dinaphthylethylene molecule in an excited state are calculated in the first and second approximations of the parametric method employed in the theory of vibronic spectra. The calculated spectra are in quantitative agreement with experimental data. The role of the angular parameters of the parametric method in the quantitative prediction of the vibrational structure of the fluorescence spectrum and changes observed in the geometry of the dinaphthylethylene molecule under excitation is determined. It is demonstrated that the polyene and acene parameters of the parametric method possess a high degree of transferability and that the models obtained are quite adequate to the real structures of the molecules under investigation. The proposed approach permits qualitative predictions and quantitative predictive calculations of the spectra of the studied molecules, as well as the spectral characteristics necessary for simulation of photochemical molecular transformations.     

利用IEO方法求解多原子分子的振动能谱

对于线性多原子分子体系模型,借助从海森伯方程出发的不变本征算符(IEO)方法,很方便地求解了相应哈密顿量的本征能谱与振动频率,从而给出IEO方法在分子物理中的进一步应用.     

Millimeter-wave spectrum of DCCCHO in the ground vibrational state

About 140 a- and b-type millimeter-wave transitions of propynal-d₁, DCCCHO, were measured in the ground vibrational state. The accurate rotational and centrifugal distortion constants were determined from the observed frequencies including the previous microwave measurements. Seven microwave transitions observed by infrared-microwave double resonance were also included in the analysis. The determined constants are A = 66778.016(12), B = 4463.8489(7), C = 4177.7950(7), Δ_J = 0.0015919(5), Δ_JK = −0.139214(13), Δ_K = 9.4328(18), δ_J = 0.0002885(4), δ_K = 0.03069(4), H_JK = −0.817(13) × 10⁻⁶, H_KJ = −9.62(4) × 10⁻⁶, H_K = 0.00255(8), h_J = 0.0047(3) × 10⁻⁶, in MHz.     

Submillimeter rotational spectrum of formamide in the ground vibrational state

Radio Astronomy Institute, Academy of Sciences of the Ukrainian SSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 2, pp. 213–216, February, 1991.     

Microwave spectrum of the molecular oxygen in the excited vibrational state

The fine-structure spectra of ¹⁶O₂ in the first excited vibrational state have been observed at room temperature with a double-modulation spectrometer. The spectra of an isotopic species ¹⁶O¹⁸O in the ground state are also observed in natural isotopic abundance. Revised energy formulas, which are derived as a slight extension of Tinkham and Strandberg's treatment, are used in the analyses, and much more accurate equilibrium molecular constants are determined; λ′_e = 59 429.08 ± 0.11 MHz, μ_e = ?252.265 ± 0.011 MHz, B_e = 43 336.2 ± 1.5 MHz, and $\text{r}{}_{\mathrm{e}}\text{= 1.20748 ± 0.00005}\text{A}\text{?}$.     

Study of the In2O3 molecule in the free state and in the crystal

ABSTRACT

The nanomaterials based on the In₂O₃ molecule are widely used as catalysts and sensors among other applications. In the present study, we discuss the possibility of using nanoclusters of In₂O₃ as molecular photomotors. A comparative analysis of the electronic structure of the In₂O₃ molecule in the free state and in the crystal is performed. For the free In₂O₃ molecule the geometry of its lowest structures, V-shape and linear, was optimised at the CCSD(T) level, which is the most precise computational method applied up to date to study In₂O₃. Using experimental crystallographic data, we determined the geometry of In₂O₃ in the crystal. It has a zigzag, not symmetric structure and possesses a dipole moment with magnitude slightly smaller than that of the V-structure of the free molecule (the linear structure due to its symmetry has no dipole moment). According to the Natural Atomic population analysis, the chemical structure of the linear In₂O₃ can be represented as O = In?O?In = O; the V-shaped molecule has the similar double- and single-bond structure. The construction of nanoclusters from ?bricks? of In₂O₃ with geometry extracted from crystal (or nanoclusters extracted directly from crystal) and their use as photo-driven molecular motors are discussed.     

Appearance of intermolecular interaction in the vibrational spectra of polyatomic XY3 molecules

We present the Raman spectra of liquid and solid PBr₃, AsCl₃, AsBr₃, and BiCl₃ between 77 and 500°K. We conjecture that ethane-like dimers of these phosphorus and arsenic trihalides exist between some temperature and the melting point. On the basis of our experimental results we analyze the change in the intramolecular force field of these molecules induced by the phase transitions and temperature, whence we calculate the frequency of vibration of the molecules relative to each other in the dimers: 2PBr₃, 2AsCl₃, 2AsBr₃. The same approach also gives the frequencies of the librational and translational modes of bismuth trichloride at 77°K.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 42–49, April, 1977.     

Oscillator strengths of the vibrational and Rydberg transitions in the 1s absorption spectrum of a nitrogen molecule

Spectral dependences of the total absorption cross sections in the region of the 1s ionization threshold of molecular nitrogen are determined for the first time with a high energy resolution using synchrotron radiation from the Russian-German channel of the BESSY II electron storage ring and continuous radiation from an x-ray tube. For N₂, partial N1s absorption cross sections are derived and the oscillator strengths for the vibrational and Rydberg transition series are evaluated from the measurements carried out with due account of the background and instrumental distortions.     

Rotational spectrum of acetonitrile CH3CN and CH3CN in a doubly excited degenerate vibrational state

The rotational spectrum of the acetonitrile molecules CH₃C¹⁴N and CH₃C¹⁵N in the degenerate vibrational state v₈ = 2 has been studied for the transitions J = 0 → 1, 2 → 3, 3 → 4, 4 → 5, 5 → 6, 6 → 7, and 7 → 8.     

Submillimeter rotational spectrum of the formamide molecule: Ground and first excited vibrational states

The results of a study of the submillimeter rotational spectrum of formamide in states v_T=0 and 1 at frequencies of 290–500 GHz are presented. More than 300 transition frequencies are identified. Watson Hamiltonian constants are obtained for both states.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 2, pp. 259–264, February, 1994.     

Microwave spectrum of 35ClO in the excited vibrational state and a comment on the centrifugal distortion constant

The $\text{J =}\text{3}\text{2}\text{←}\text{1}\text{2}$ transitions of ³⁵ClO in v = 1 of the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state were measured and analyzed to obtain the following constants (in megahertz: B = 18 444.86 ± 0.18, p_eff = 669.32 ± 1.08, $\text{a ? (b + c)}\text{2}\text{= 157.05 ± 0.97}$, d = 169.77 ± 0.99, and eqQ = ? 84.78 ± 0.30. The equilibrium bond length is calculated to be 1.56954 ± 0.00005 Å. The transitions in the ground vibrational state, which were reported previously, were reanalyzed by taking into account the matrix elements off diagonal in J of the hyperfine interactions, and led to a refined centrifugal distortion constant, 0.0476 ± 0.0154 MHz. The vibrational frequency increased accordingly to 782 ± 126 cm^?1, which agreed with the value 870 ± 90 cm^?1 obtained from a relative-intensity measurement, and also with other optical spectroscopic data.