The Ground State of D(2)Se and HDSe

Ground state rotational constants of D(M)(2)Se and HD(M)Se, M = 76, 77, 78, 80, and 82, have been determined up to octic centrifugal distortion terms from ground state combination differences. These were obtained from rotational analyses of the nu(2), nu(1), and nu(3) bands both of natural and (80)Se monoisotopic material recorded with a resolution of ca. 3 x 10(-3) cm(-1). While the full set of rotational parameters of the (80)Se species was determined with significance, some of the centrifugal distortion terms of the less abundant species were either constrained to those of the (80)Se species or extrapolated. Copyright 1999 Academic Press.

High-Resolution FTIR and Millimeter-Wave Study of D(3)SiF: The Ground, v(3) = 1, and v(6) = 1 and 2 States

The nu(6) (555.453 cm(-1)), the nu(3) (888.899 cm(-1)), and the very weak 2nu(6) infrared bands (2nu(-/+2)(6) 1101.734 cm(-1), 2nu(0)(6) 1100.102 cm(-1)) for the (28)Si species of D(3)SiF have been recorded with a resolution of 3.3, 2.4, and 5.0 x 10(-3) cm(-1), respectively. Millimeter-wave spectra up to 640 GHz of D(3)SiF in the ground, v(3) = 1, and v(6) = 1 and 2 states were measured. Ground state constants complete up to H constants including the K-dependent parameters A(0), D(0)(K), and H(0)(K) as obtained by the nu(+/-1)(6)/2nu(+/-2)(6)-nu(+/-1)(6)/2nu(-/+2)(6) loop method were determined by a merge of 2388 ground state combination differences with 59 rotational data. The v(3) = 1 and v(6) = 1 and 2 levels appear to be unperturbed intervibrationally for the J and K values that could be accessed. However, Deltal = Deltak = +/-2 and Deltal = +/-2, Deltak = -/+4 interactions affect the v(6) = 1 level while the v(6) = 2 levels undergo three interactions of Deltal = Deltak = +/-2, Deltal = +/-2, Deltak = -/+1 and Deltal = +/-4, Deltak = -/+2 type. Typically, for the different bands, 2000-4000 pieces of infrared data augmented by 36-120 rotational data were fitted together. Owing to the weakness of the 2nu(6) band, the body of v(6) = 2 data was enlarged by energies that are deduced from the 2nu(6)-nu(6) and nu(6) bands and which span in particular high K values. Comparison with available ab initio data derived from the harmonic and anharmonic force fields is made. Copyright 1999 Academic Press.

Isotope Substitution in Near Local Mode H(2)X Molecules: The nu(1) and nu(3) Bands of D(2)Se

The high-resolution (0.0027 cm(-1)) Fourier transform spectra of the D(2)Se molecule as (80)Se monoisotopic and natural material were recorded for the first time in the 1500-1900 cm(-1) region where the nu(1) and nu(3) vibration-rotation bands are located. Because accurate information about the rotational structures of different vibrational states was still lacking, the isotopic relations between rotational, centrifugal distortion, resonance interaction, etc., parameters of the H(2)Se and D(2)Se species were derived and successfully used for the construction of a synthetic spectrum for the nu(1) and nu(3) bands. As a result, lines of the recorded spectrum were assigned, and band centers, rotational, centrifugal distortion, and resonance interaction parameters for the (100) and (001) states of the species D(2)(M)Se, M = 76, 77, 78, 80, and 82, were determined. The obtained sets of parameters reproduce values of the vibration-rotation energies with a "mean" accuracy of 0.00007 cm(-1) for the D(2)(80)Se, and a slightly worse accuracy for other Se isotopic species. Copyright 1999 Academic Press.

H(3)Si(37)Cl Revisited with High Resolution: The Ground State and the v(2) = 1; v(3) = 1, 2, and 3; v(5) = 1; v(6) = 1 and 2; and v(3) = v(6) = 1 States

The infrared spectrum in the range 400-1600 cm(-1) of isotopically pure H(3)Si(37)Cl has been recorded at high resolution (2.4-6.6 x 10(-3) cm(-1)) and analyzed. Fifteen bands have been studied, namely the four fundamentals nu(3) (543.968 cm(-1)), nu(6) (663.738 cm(-1)), nu(2) (947.982 cm(-1)), and nu(5) (950.657 cm(-1)), the overtone bands 2nu(3), 2nu(0)(6), and 2nu(-/+2)(6), the combination band nu(3) + nu(6), and seven hot bands. Improved ground state constant parameters have been obtained, including all four sextic distortion constants. As for the J-independent parameters A(0), D(0)(K), and H(0)(K), they were determined mainly through the "loop method" involving nu(6), 2nu(-/+2)(6), and 2nu(-/+2)(6)-nu(+/-1)(6) and checked through the strong interactions between nu(2) and nu(5), producing some "forbidden lines." The nu(2)/nu(5) dyad was fitted with success using two different reduced Hamiltonians. Concerning nu(3) and nu(6), in spite of their relatively large separation, a Coriolis interaction could be evidenced. In both nu(2)/nu(5) and nu(3)/nu(6) interacting systems the sign of the interaction was found positive. As for the overtones, 2nu(3) was treated as isolated and 2nu(0)(6) and 2nu(-/+2)(6) as linked together by an l(2, 2) interaction. The data on the v(3) = v(6) = 1 levels were obtained mainly from the two hot bands nu(3) + nu(6) - nu(3) and nu(3) + nu(6) - nu(6), and marginally from the weak band nu(3) + nu(6), and also fitted as for an isolated level. A weak x,y-Coriolis interaction with level crossing between K/(kl - 1) = 21 and 22, and a local l(1, -2) resonance at K = 13/kl = -15 between 2nu(3) and nu(5) were furthermore detected. Copyright 1999 Academic Press.

Radio-Frequency, Centimeter-Wave, Millimeter-Wave, and Infrared Spectra of SiDF(3) in the v(6) = 1 Excited State

This paper deals with the first study of high-resolution radio-frequency, centimeter-wave, millimeter-wave, and infrared spectra of the deuterated isotopomer of trifluorosilane, SiDF(3), in its lowest degenerate excited v(6) = 1 state. Following the work of E. I. Lobodenko, O. N. Sulakshina, V. I. Perevalov, and Vl. G. Tyuterev, (J. Mol. Spectrosc. 126, 159-170 (1987)) and Harder (J. Mol. Spectrosc. 194, 145 (1999)), the data (18 A(1)-A(2) transitions, 229 l-type resonance transitions, 189 pure rotational transitions, and 1167 rovibrational transitions) have been fitted using three equivalent Q, D, and QD reduction schemes enabling the fit of one of the three interaction parameters d, q(12), and epsilon, respectively, while the other two are fixed to zero. In addition to further higher order constants, either f(K)(22) or tau(K) also had to be constrained. By checking the standard deviation of each data set and the relations between parameters determined within different constrains, the six reduction schemes have been shown to be unitary equivalent. Furthermore, the axial rotational ground state constant C(0) has been accurately determined. Copyright 1999 Academic Press.

Mid- and Near-Infrared Spectra, Millimeterwave Spectra, and Global Analysis of (16)O(12)C(80)Se

We have recorded a total of 12 FTIR spectra of monoisotopic OC(80)Se in different spectral regions with a resolution (1/maximum optical path difference) between 2.7 and 13.2 x 10(-3) cm(-1). These spectra spanned the range from 350 to 7800 cm(-1), many bands being studied with different p x L products in order to also detect weak hot bands. Altogether 18 band systems comprising 81 different bands, mostly of Sigma type, were observed and analyzed by means of polynomial expansions in J(J + 1). New rotational transitions of vibrationally excited states as high as 2200 cm(-1) with J" 17-25 in the 140-210 GHz and J" 53-58 in the 430-470 GHz millimeterwave regions were measured with the assistance of predictions by the global fit. This fit was performed using a weighted least-squares procedure and employing the whole body of data, and about 100 molecular parameters were determined that describe the energy level of (16)O(12)C(80)Se with statistical accuracy. Improved highly accurate ground state parameters up to sextic centrifugal distortion terms were obtained by a merge of ground state combination differences and pure rotational data. The v(1), v(2), v(3) polyad interacts anharmonically with the v(1) - 1, v(2) + p, v(3) + q polyads with p + 2q = 4. Moreover, some local crossings with Coriolis interactions between (v(1), v(2), v(3)) and (v(1) - 1, v(2) + 3, v(3) + 1) levels were observed and treated perturbationally. Copyright 1999 Academic Press.

Telomerase is a highly sensitive and specific molecular marker in fine-needle aspirates of breast lesions

PURPOSE

Telomerase has been detected in a majority of human malignant tumors, making telomerase activity (TA) one key difference between mortal and immortal cells. In this study, we evaluated in blind-trial fashion the association of TA with cytologic and final clinical/pathologic diagnosis in fine-needle aspirates (FNAs) of breast lesions.

MATERIALS AND METHODS

In 172 FNAs, including 80 samples that were cytologically malignant, 18 that were atypical but not diagnostic for malignancy, and 74 that were cytologically benign, TA was determined by a modified nonradioactive telomeric repeat amplification protocol (TRAP) assay. Final diagnosis was made by pathologic examination of follow-up surgical material available for all the cytologically malignant samples, a majority of the cytologically atypical samples, and a portion of the cytologically benign samples.

RESULTS

TA was detected in 85 of 172 samples. Comparison of the cytologic and histologic diagnoses with TA showed that 80 of 87 samples from patients with breast cancer were telomerase-positive, resulting in a sensitivity of 92%. TA was found in four of five FNAs from carcinomas that were considered cytologically atypical but not diagnostic for malignancy. Eighty of 85 samples from patients with benign breast lesions were telomerase-negative, revealing a specificity of 94%. The five positive cases in this group were all fibroadenomas with low TA. Among the 18 cases with a cytologic diagnosis of atypia, there was a strong positive relationship between TRAP findings and histologic diagnosis.

CONCLUSION

The detection of TA in FNAs of breast lesions is a highly sensitive and specific marker of malignancy and may be used as an adjunct in cases with an equivocal cytologic diagnosis.

High-Resolution Infrared Spectra and Simultaneous Rovibrational Analysis of the nu2, nu3, nu5, and nu6 Bands of H3SiF

A high-resolution FT infrared spectrum of H3SiF (resolution 0.0024 cm-1) in the region 620-1130 cm-1 was measured and used to analyze the fundamental bands nu2 (A1), 990.851 cm-1; nu3 (A1), 875.011 cm-1; nu5 (E), 962.213 cm-1; and nu6 (E), 729.528 cm-1. A total number of 7241 transition wavenumbers (including 53 perturbation-allowed transitions) with J' </= 49 have been fitted by taking into account various Coriolis interactions, alpha-resonance terms, and l-type interactions between and within the vibrational levels v2 = 1, v3 = 1, v5 = 1, and v6 = 1. The strongest interaction in this system of levels is the x-y Coriolis coupling between the v2 = 1 and v5 = 1 vibrational states. However, it turns out that the x-y and z-type Coriolis interactions also have to be introduced explicitly between the v5 = 1 and v6 = 1 states as well as the x-y Coriolis interactions between v3 = 1 and v5 = 1, and v3 = 1 and v6 = 1 states, in order to fit the data quantitatively. The standard deviation of the fit was varsigma = 8.6 x 10(-5) cm-1 for 7241 transition wavenumbers and 68 fitted parameters. The sign relations between the fitted parameters and the possibility of fitting the parameters in different schemes are discussed. The results have been used to find close coincidences between the frequencies of the CO2 laser lines and the transition wavenumbers of the nu2 and nu5 bands of H3SiF for the main natural isotopomer. We report integrated absorption band strengths which are important for infrared laser chemistry. Copyright 1999 Academic Press.

[Comparative genomic hybridization (CGH) for detecting a heretofore undescribed amplified chromosomal segment in high-grade medullary osteosarcoma]

Osteosarcoma is one of the most commonly biopsied primary tumor of bone. High-grade osteosarcomas in particular exhibit a wide spectrum of cytogenetic changes. Molecular cytogenetic studies on osteosarcomas have shown that genomic amplification, especially of both the TP53-binding MDM2 gene and the flanking SAS gene, plays an important role in the biology of these tumors. We applied CGH in order to obtain a global view of DNA-sequence losses and gains in osteosarcoma. CGH was performed on 20 high-grade medullary osteosarcomas (13 primary tumors prior to chemotherapy, 5 tumors after chemotherapy, 2 established cell lines [MB63, HOS58]) using genomic DNA of snap-frozen tumor specimens. CGH revealed DNA copy number aberrations, mostly gains, in all the tumors studied with an average of 18.5 aberrations/tumor (range 8-32). High-level amplifications were observed in all cases (average 4.1 amplifications/tumor [range 1-10]). Amplicons affecting at least five tumors were mapped to 1p21-31 (9/20 cases), 3q25-qter (6/20), 6p12-21 (6/20), 8q12-qter (10/20), 12p11-12 (9/20), 12q12-15 (enclosing MDM2 and SAS loci, 7/20). Losses were most frequently seen at 3p, 10q, 11p and 13 (all 10/20). In conclusion, our CGH data indicated that genomic amplification plays an important role in the biology of osteosarcoma. CGH demonstrated the complexity of genetic aberrations in osteosarcomas. The detection of novel non-random DNA amplifications in our study has defined regions for further targeted molecular genetic research aimed at identifying those oncogenes that are characteristic of osteosarcoma development.

The Interacting v6 = 2 Levels of D3Si35Cl: A Tool to Determine Ground State Constants from High-Resolution Spectra in the 440-590 and 900-1100 cm-1 Regions

High-resolution FTIR spectra of monoisotopic D3Si35Cl have been recorded in the regions 440-590 cm-1 (nu3/nu6) and 900-1100 cm-1 (2nu6/nu3 + nu6/2nu3). A detailed rovibrational study was done for the 2nu06, 2nu-/+26, and 2nu3 overtone bands and for the 2nu+/-26-nu+/-16, 2nu06-nu-/+16, and (nu3 + nu+/-16)-nu+/-16 hot bands. For the first time the interactions occurring between the v6 = 2, v3 = v6 = 1, and v3 = 2 levels of any trideuterated silyl halide have been analyzed. The (nu3 + nu+/-16)-nu+/-16 hot band served to obtain accurate energies of the v3 = v6 = 1 level, the nu3 + nu6 combination band not being detectable on our spectra. The first experimental determination of A0 and D0K for this molecule was undertaken by a well-established method, using the nu6, 2nu+/-26-nu+/-16, and 2nu-/+26 bands. Ground state energy differences DeltaK(J) = E0(J, K) - E0(J, K - 3) were calculated for K values from 2 to 16. By a least-squares fit of 163 such differences, the A0 and D0K values thus obtained were (in cm-1): A0 = 1.4278230(8) and D0K = 5.3916(31) x 10(-6). Copyright 1999 Academic Press.

The Coriolis-Coupled States v7 = 1 and v9 = 1 of trans-HCOOD and trans-DCOOD

The Fourier transform gas-phase infrared spectra of the two lowest Coriolis-perturbed nu7 and nu9 bands of deuterated formic acid HCOOD and DCOOD have been measured with a resolution of ca. 0.003 cm-1. Combined analysis of the assigned IR transitions and all the available rotational data have allowed the determination of the band centers, rotational and centrifugal distortion parameters, and Coriolis coupling terms. Standard deviations of the IR transitions are 0.000246 cm-1 for HCOOD and 0.000209 cm-1 for DCOOD. Determined band centers are nu0(nu7) = 558.2723 cm-1, nu0(nu9) = 508.1321 cm-1 for HCOOD and nu0(nu7) = 554.4397 cm-1, nu0(nu9) = 492.2254 cm-1 for DCOOD. Copyright 1999 Academic Press.

High-Resolution Infrared Spectrum of nu5, nu4, nu3, nu4 + nu5, and 2nu4 Band Systems of Deuterobromoacetylene

High-resolution vibration-rotation spectra of gas-phase deuterobromoacetylene have been recorded in the 240-990 cm-1 infrared region. The analyzed band systems are rich in hot bands and have a high density of lines. Five band systems and a total of 124 vibration-rotation bands of the isotopic species DCC79Br and DCC81Br have been rotationally analyzed. Accurate rotational parameters and vibrational wavenumbers for 33 vibrational states of each species have been obtained from the rotational analysis. l doubling and rotational l resonance have been observed on some states and the respective resonance parameters have been obtained through nonlinear least-squares optimization. A Fermi resonance block model with perturbation terms has been used for the analysis of the vibrational states. With optimized parameters, the model produces root-mean-square deviations of observed - calculated wavenumbers of about 0.3 cm-1 for both isotopic species. Copyright 1999 Academic Press.

Ab Initio Calculations and High-Resolution Spectroscopy of the Bending Pentad of SiH2D2 in the 10-16 µm Region

The SiH2D2 asymmetric top has nine vibrational modes, five of them forming a pentad strongly perturbed by Coriolis interactions. High-level ab initio calculations of SiH2D2 have been performed which yield numerous spectroscopic parameters related to the harmonic and anharmonic force fields. The bending pentad comprising nu4(A1), nu7(B1), nu5(A2), nu9(B2), and nu3(A1) has been studied by high-resolution Fourier transform spectroscopy; the region 600-1050 cm-1 has been investigated with a resolution of ca. 4 x 10(-3) cm-1. Raman BOXCARS spectroscopy has been used for the infrared inactive nu5 band. The Raman apparatus function was 0.0054 cm-1. Assignments of about 4000 transitions including all bands have been made, mostly employing ground state combination differences techniques, and a global fit has been performed. The fundamentals nu4 (681.624 cm-1), nu7 (742.640 cm-1), nu5 (842.381 cm-1), nu9 (859.750 cm-1), and nu3 (942.741 cm-1) are strongly coupled by A-, B-, and C-type Coriolis interactions, and ab initio predictions of these interaction parameters were used to set up a network of interactions that was refined by the experimental data. The global standard deviation for the entire body of data is 7.1 x 10(-4) cm-1. Satisfactory synthetic spectra which are very sensitive to relative signs of dipole moment derivatives and Coriolis interaction constants were obtained with the guidance of ab initio calculations. Finally, fair to good agreement of experimental and ab initio calculated molecular parameters was obtained. For the first time, a complete analysis of the pentad of SiH2D2 in the 10-16 µm region has been carried out. A full set of rovibrational parameters is given for these five interacting levels, including first and second order Coriolis interaction constants. Copyright 1998 Academic Press.

High-Resolution Study of the First Stretching Overtones of H3Si79Br

The Fourier transform infrared spectrum of monoisotopic H3Si79Br (resolution 7.7 x 10(-3) cm-1) was studied from 4200 to 4520 cm-1, in the region of the first overtones of the Si-H stretching vibration. The investigation of the spectrum revealed the presence of two band systems, the first consisting of one parallel (nu0 = 4340.2002 cm-1) and one perpendicular (nu0 = 4342.1432 cm-1) strong component, and the second of one parallel (nu0 = 4405.789 cm-1) and one perpendicular (nu0 = 4416.233 cm-1) weak component. The rovibrational analysis shows strong local perturbations for both strong and weak systems. Seven hundred eighty-one nonzero-weighted transitions belonging to the strong system [the (200) manifold in the local mode picture] were fitted to a simple model involving a perpendicular component interacting by a weak Coriolis resonance with a parallel component. The most severely perturbed transitions (whose ||obs-calc || values exceeded 3 x 10(-3) cm-1) were given zero weights. The standard deviations of the fit were 1.0 x 10(-3) and 0.69 x 10(-3) cm-1 for the parallel and the perpendicular components, respectively. The weak band system, severely perturbed by many "dark" perturbers, was fitted to a model involving one parallel and one perpendicular band, connected by a Coriolis-type resonance. The K" . DeltaK = +10 to +18 subbands of the perpendicular component, which showed very high observed - calculated values ( approximately 0.5 cm-1), were excluded from this calculation. The standard deviations of the fit were 11 x 10(-3) and 13 x 10(-3) cm-1 for the parallel and the perpendicular components, respectively. Copyright 1998 Academic Press.

Fourier Transform Spectroscopy of the nu3 and nu6 Bands of D3Si35Cl: Rovibrational Constants of the v = 0, v3 = 1, and v6 = 1 States

The nu3 and nu6 infrared bands near 500 cm-1 of monoisotopic D3Si35Cl have been studied with a resolution of 3.3 x 10(-3) cm-1. More than 800 transitions of nu3 and 2600 of nu6 have been assigned and fitted to ground and excited state parameters, final sigma(Fit) = 2.93 x 10(-4) cm-1. Ground state parameters up to quartic terms have been obtained. The excited state model included l(2, 2) and l(2, -1) interactions within nu6 and Coriolis x, y resonance between nu3 and nu6, interaction parameters being determined with high significance in all cases. The band centers nuo were determined, nu3 = 538.502 cm-1 and nu6 = 491.260 cm-1. Excellent agreement of experimental parameters with those from the ab initio harmonic and anharmonic force fields is noted. The transition moment ratio, ||µ3:µ6 || = 1:0.6(1), was determined by band contour simulation. Copyright 1998 Academic Press.

Analysis of the Rotational Spectra of SiH3CN and Its Isotopomers: Experimental and Ab Initio Determinations of the Dipole Moment and the Structure

The ground state rotational spectra of SiH3CN and its 29Si, 30Si, 13C, 15N, d1, d2, and d3 isotopic species have been measured by Fourier transform microwave spectroscopy and by millimeterwave spectroscopy. Accurate rotational, centrifugal distortion, and 14N and D nuclear quadrupole coupling constants have been derived. The dipole moment of the parent species has also been measured, µ = 3.4400(42) D. The structure, force field, dipole moment, and nuclear quadrupole coupling constants have been calculated ab initio at the SCF, MP2, and B3LYP levels using triple zeta polarized basis sets. The experimental ro, rs, and rz structures have been determined. An approximate equilibrium structure has been obtained by combining the experimental results and the ab initio calculations: re(C&tbond;N) = 1.159 Å, re(Si&sbond;C) = 1.848 Å, re(Si&sbond;H) = 1.470 Å, and angle(HSiC) = 107.4 degrees. Copyright 1998 Academic Press.

Chromosomal aberrations associated with invasion in papillary superficial bladder cancer

Non-invasive and invasive papillary transitional cell carcinomas of stages pTa and pT1 represent the first steps of tumour progression in bladder cancer. In order to analyse different chromosomal alterations of pTa and pT1 superficial bladder cancer, 46 tumour specimens were examined by comparative genomic hybridization (CGH). Losses of chromosome 9 material (11/20) and gains of chromosome 17 material (6/20) were frequently found in pTa tumours. Stage pT1 tumours were characterized by gains of chromosome 1q (14/26; including amplification at 1q21-q24 in three cases) and chromosome 17 material (15/26), as well as by losses of 11p (15/26) and 11q (13/26). Other loci frequently showing losses in pT1 tumours were 2q (9/26), 4q (10/26), 5q (9/26), 8p (10/26), 9p (9/26), 9q (12/26), 10q (8/26), 17p (7/26), and 18q (8/26). Amplifications were detected at 8q21/22, 5q21, 7q36, 10p14, 10p12, 10q25, 12q12, and 12q14. The most striking differences between grade 2 pTa and pT1 tumours were gains of 1q (P < 0.01) and losses at 2q (P < 0.025), 10q (P < 0.05), 11p (P < 0.01), 11q (P < 0.01), and 17p (P < 0.05), as well as the total number of aberrations (pTa grade 2: 4.1; pT1 grade 2: 8.6 aberrations per tumour). These data show characteristic chromosomal aberrations associated with invasion in superficial bladder cancer.

Diode Laser and FTIR Spectroscopy of BrCN Isotopomers in the Region of the nu3 Band

The nu3 fundamental band (C-N stretch) and four associated hot bands (01(1)1-01(1)0, 10(0)1-10(0)0, 02(0)1-02(0)0, and 02(2)1-02(2)0) of natural 79/81Br12C14N have been recorded and analyzed in the 4.8-µm region using an FTIR spectrometer. Analyses of the same hot bands, previously recorded using a diode laser spectrometer, are also presented for the 13C and 15N isotopically labeled species. Copyright 1998 Academic Press.

High Resolution FTIR Study of the nu5 Bands of HSiD3 and H120SnD3

High resolution Fourier Transform spectra of HSiD3 and monoisotopic H120SnD3 have been recorded in the region of the nu5 fundamental at 850.68 and 646.90 cm-1 with a resolution of 3.3 and 2.8 x 10(-3) cm-1, respectively. About 2000 rovibrational transitions of each species have been assigned and fitted to two different reductions of the effective Hamiltonian, with sigma(Fit) = 1.2 x 10(-4) (HSiD3) and 1.4 x 10(-4) cm-1 (H120SnD3). The two sets of parameters were shown to be equivalent, and relations between parameters belonging to different reductions are perfectly fulfilled. Furthermore the ground state constants C0 and DK0 have been determined for the first time. For consistency the previously measured data belonging to the nu5 band of H70GeD3 have been refitted, sigma(Fit) = 1.6 x 10(-4) cm-1, on the basis of improved ground state parameters including the h'3 term accounting for the splitting of the K = 3 level. Copyright 1998 Academic Press.

High-Resolution FTIR Study of Thiocarbonyl Difluoride SCF2

High-resolution ( approximately 3 x 10(-3) cm-1) FTIR spectra of the planar SCF2 molecule have been recorded in the range of the four lowest-lying fundamentals nu2 (789.535 cm-1), nu3 (526.697 cm-1), nu5 (419.546 cm-1), and nu6 (623.187 cm-1). For each band 4500-7500 transitions have been assigned and fitted to a standard Watson-type Hamiltonian up to quartic terms, sigma(Fit) approximately 3.5 x 10(-4) cm-1. No indication of rovibrational perturbations was found, excited state rotational and centrifugal distortion constants being close to their ground state values. Ground state parameters previously determined from microwave spectra were, in part, improved by a merge of the appropriately weighted microwave data and approximately 10 000 ground state combination differences that were obtained from the nu4 band and spanning J and Ka values of 88 and 49, respectively. Copyright 1998 Academic Press.

The First Si-H Stretching Overtone of H3SiD: Emergence of Local Mode Effects

The FTIR spectrum of H3SiD in the 4100-4500-cm-1 region was recorded at Doppler-limited resolution, and four bands were studied. At lower wavenumbers, two strong bands, which in the local mode picture can be assigned to (200, E) (nu0 = 4308.5667 cm-1) and (200, A1) (nu0 = 4307.8441 cm-1), were analyzed, and at higher wavenumbers, two weaker bands, namely (110, E) at 4378.1950 cm-1 and (110, A1) at 4375.9763 cm-1, were analyzed. A total number of approximately 1900 lines in the strong dyad and 1000 lines in the weak one were assigned and fitted with standard deviations of the residuals approximately 0.0008 cm-1. The strong system (200) is close to local mode behavior, with no x, y Coriolis term needed and only a small z Coriolis term, and simple arithmetic relations between vibration-rotation parameters are fulfilled as expected. The local mode behavior of the weak system (110) is less pronounced, but z and x, y Coriolis effects are smaller than in the Si-H stretching fundamentals. Comparison of computed and observed spectra provided a good estimate for the ratios of transition moments of the different bands: they are, in absolute value, proportional to 3.5:1.75:1:1 for (200, E), (200, A1), (110, E), and (110, A1), respectively. Copyright 1998 Academic Press.