Wavelength measurements of 13C16O laser transitions

Wavelength measurements of 160 ¹³C¹⁶O laser lines in the range from 1500 to 1900 cm^?1 have been made with a conventional grating spectrometer. The accuracy of the measurements is about ±0.003 cm^?1. Although more precise measurements of these lines will ultimately be made using microwave beating techniques, the present results should be of interest for the determination of improved molecular constants for CO and especially for the various spectroscopic applications of the CO laser.     

Tunable infrared diode laser measurements of line strengths and collision widths of 12C16O at room temperature

A tunable diode laser was used to scan 33 vibration-rotation lines in the fundamental band of CO in room-temperature CO-N₂ and CO-Ar mixtures. Each absorption record was fitted with a Voigt profile from which the line strength and collision width were determined. The fundamental band strength of ¹²C¹⁶O at 273.2°K was determined to be 283±4 cm^-2 atm^-1. Results are also presented for the rotational quantum number dependence of the collision width for broadening by N₂ and Ar.     

Statistical fluctuations and compound elastic scattering for 12C(12C, 12C)12C and 16O(16O, 16O)16O

The difference between the observed fluctuations in the elastic excitation functions for carbon-carbon and oxygen-oxygen scattering, just above the Coulomb barrier, is interpreted in terms of the compound nucleus model.     

A precise study of the rotational spectrum of formaldehyde H212C16O,H213C16O,H212C18O,H213C18O

The rotational spectra of formaldehyde, H₂¹²C¹⁶O and its isotopic species H₂¹³C¹⁶O, H₂¹²C¹⁸O, and H₂¹³C¹⁸O have been investigated in the ground vibrational state in the frequency region between 8 and 460 GHz. For most cases in which measurements of the a-type R- and Q-branch transitions already existed the accuracy of the line position has been improved to about 10 kHz. For H₂¹²C¹⁶O and H₂¹³C¹⁶O a large number of ΔK_a = ±2 transitions were measured with similar accuracy. These new data when combined with all other available data and appropriate weightings lead to a set of ground state parameters which for the first time are compatible with infrared and ultraviolet data. The rotational constants (and 3σ standard deviations) obtained using Watson's A-reduced Hamiltonian are:

     

5.

The infrared spectra of ¹²C³²S, ¹²C³⁴S, ¹³C³²S,and ¹²C³³S     

Terry R. Todd  Wm.Bruce Olson 《Journal of Molecular Spectroscopy》1979,74(2):190-202

Using a tunable diode laser spectrometer, the infrared absorption spectra of four isotopic species of carbon monosulfide have been observed in the positive column of a dc discharge of CS₂ and Ar. The wavenumbers of 115 vibration-rotation transitions between 1180.5 and 1266.1 cm^?1 have been measured. These lines were assigned to the 1-0, 2-1, 3-2, and 4-3 bands of ¹²C³²S, the 1-0 and 2-1 bands of ¹²C³⁴S and ¹³C³²S, and the 1-0 band of ¹²C³³S. These new data have been combined with the previous infrared and microwave results to determine Dunham coefficients (Y_ij), the Dunham potential expansion constants (a₀,a₁,a₂,a₃, and a₄), and the classical turning points by the RKR method.     

6.

Low energy fusion of ¹²C + ¹²C and ¹⁶O + ¹⁶O systems     

P.-H. Heenen 《Physics letters. [Part B]》1981,99(3):298-300

The adiabatic time-dependent Hartree-Fock method (ATDHF) is applied to the calculation of low energy fusion of ¹²C + ¹²C and ¹⁶O + ¹⁶O systems. The energy dependence of the results is in good agreement with experiment, while the order of magnitude is not correct. It is shown that the dynamical effects included in ATDHF are very important and cannot be neglected at the energies of astrophysical interest.     

7.

Helium and self-broadening in the first and second overtone bands of ¹²C¹⁶O     

Joseph J. BelBruno  Jack Gelfand  William Radigan  Keith Verges 《Journal of Molecular Spectroscopy》1982,94(2):336-342

The pressure broadening coefficients for rotation-vibration lines of J states up to 22 in the 2-0 band and J states up to 20 in the 3-0 band of pure CO and HeCO mixtures were measured. The data were obtained at room temperature utilizing a Fourier transform spectrometer and various cells, including a 113-m White cell. These data exhibit little change with increasing vibrational level, and in the case of helium broadening, only slight J dependence.     

8.

Determination of laser line frequencies and vibrational-rotational constants of the ¹²C¹⁸O₂, ¹³C¹⁶O₂, and ¹³C¹⁸O₂ isotopes from measurements of CW beat frequencies with fast HgCdTe photodiodes and microwave frequency counters     

Charles Freed  A.H.M. Ross  Robert G. O&#x;Donnell 《Journal of Molecular Spectroscopy》1974,49(3):439-453

The frequencies of ¹²C¹⁸O₂, ¹³C¹⁶O₂, and ¹³C¹⁸O₂ isotope lasers have been measured to better than 3 MHz (0.0001 cm^?1) by comparing with a ¹²C¹⁶O₂ reference laser. Heterodyne techniques were used to generate 139 difference frequencies in a liquid nitrogen cooled HgCdTe photodiode. Microwave frequency counter measurements of the difference frequencies were then used to calculate new values for the band centers and rotational constants of the rare isotopes. Procedures to achieve further improvements are discussed.     

9.

Absolute frequency measurements of N₂O laser transitions     

B.G. Whitford  K.J. Siemsen  H.D. Riccius  G.R. Hanes 《Optics Communications》1975,14(1):70-74

The absolute frequencies of 33 P- and R-branch lines of the N₂O, 00°1–10°0 laser band have been measured by heterodyning with known CO₂ laser frequencies of the 00°1 – 10°0 band in a tungsten-nickel diode. These measurements were used to calculate more precise values for the band centre and for the rotational constants.     

10.

The ν₃ band of ¹⁶O¹²C³⁴S and ¹⁶O¹³C³⁴S     

Ghislain Blanquet  Jacques Walrand  Charles P. Courtoy  André Fayt 《Journal of Molecular Spectroscopy》1980,81(2):473-479

The ν₃ fundamental of OCS has been measured with a resolution of about 0.03 cm^?1 for the isotopic species ¹⁶O¹²C³⁴S and ¹⁶O¹³C³⁴S. The associated transition 01¹1-01¹0 has also been measured. The transition 10⁰1-00⁰0 is also reported for the ¹⁶O¹²C³⁴S species.     

11.

Radiative pion capture in ¹²C and ¹⁶O     

Ohtsubo Hisao  Nishiyama Toshio  Kawaguchi Masaaki 《Nuclear Physics A》1974,224(1):164-185

Radiative pion capture in ¹²C and ¹⁶O is investigated. An effective interaction Hamiltonian based upon the CGLN theory is employed. Capture rates in ¹²C and ¹⁶O from Is and 2p pionic orbits are calculated by using the nuclear model of Kamimura, Ikeda and Arima for the odd parity states of ¹²C, and that of Walker with strong ground state correlations, for the odd parity states of ¹⁶O. The results are compared with those of the 1p-1h nuclear model under the Tamm-Dancoff and random phase approximations of Gillet and Vinh Mau. Detailed examinations are made for the transitions to low-lying states with 1⁺ and 2⁺ for ¹²C and with 1^?, 2^? and 3^? for ¹⁶O by using the Cohen-Kurath and the Walker models, respectively. The results are in good agreement with the recent experimental data from Berkeley.     

12.

Improved rovibrational constants and frequency tables for the normal laser bands of ¹²C¹⁶O₂     

F.Russell Petersen  Earl C. Beaty  C.R. Pollock 《Journal of Molecular Spectroscopy》1983,102(1):112-122

New frequency difference measurements between Doppler-free stabilized laser lines in the 9.4- and 10.4-μm bands of ¹²C¹⁶O₂, including high-J and across-the-band-center measurements, have made significant improvements in the rovibrational constants. The absolute frequencies were referred to the methane stabilized 3.39-μm HeNe laser. Frequency tables generated from these constants have absolute uncertainties of less than two parts in 10¹⁰ and are about a factor of 10 better than older tables. In addition, the laser lines P_I(50) in ¹³C¹⁶O₂ and R_II(26) in ¹³C¹⁸O₂, which were used as reference lines in recent visible laser frequency measurements, were also measured to about the same accuracy.     

13.

¹⁶O(p,α₀)¹³N cross-section measurements     

A.V. Nero  A.J. Howard 《Nuclear Physics A》1973,210(1):60-66

Total cross sections for the ${}^{16}\text{O}\text{(}\text{p}\text{, α}{}_0\text{)}{}^{13}\text{N}$ reaction have been measured by observation of the positron decay of the residual ¹³N nuclei. These cross sections, covering the c.m. energy range 5.4 ≦ E ≦ 9.9 MeV, allow determination of reaction rates of astrophysical interest at temperatures in the neighborhood of 4 × 10⁹°K.     

14.

Phase-shift analysis of ¹⁶O + ¹⁶O elastic scattering     

H. Voit  H.-D. Helb 《Nuclear Physics A》1973,204(1):196-202

A phase-shift analysis has been carried out for ¹⁶O + ¹⁶O elastic scattering, resulting in unambiguous values for the reflection coefficients in the energy range of the first gross structure of the 90° excitation function, and answering some of the questions still open regarding the calculations existing so far.     

15.

The infrared spectrum of ¹²C³²S and ¹²C³⁴S     

Terry R. Todd 《Journal of Molecular Spectroscopy》1977,66(1):162-167

The 2-0 vibration-rotation bands of ¹²C³²S and ¹²C³⁴S near 2530 cm^?1 have been measured with a high resolution spectrometer. The spectroscopic constants for these bands are given, as well as an improved set of Dunham coefficients for the X¹Σ⁺ state of ¹²C³²S.     

16.

A precise study of the rotational spectrum of formaldehyde H₂¹²C¹⁷O and H₂¹³C¹⁷O     

R. Cornet  B.M. Landsberg  G. Winnewisser 《Journal of Molecular Spectroscopy》1980,82(2):253-263

The pure rotational spectra of H₂¹²C¹⁷O and H₂¹³C¹⁷O have been investigated in the frequency region between 8 and 360 GHz in the ground vibrational state. For both isotopic species the ¹⁷O nuclear quadrupole coupling constants and spin-rotation constants have been obtained. From both Q- and R-branch transitions a set of rotational constants and several distortion constants could be derived employing Watson's formalism in A reduction. The obtained rotational constants are in Megahertz:

	H212C16O	H213C16O	H212C18O	H213C18O
A/MHz	281 970.572 (24)	281 993.258(135)	281 961.94 (39)	281 985.00 (93)
B/MHz	38 836.0456(13)	37 811.0887(25)	36 904.1693(66)	35 859.256(10)
C/MHz	34 002.2034(12)	33 213.9790(25)	32 511.5311(63)	31 697.868(10)

     

17.

Fusion cross section of the ¹⁶O + ¹⁶O collision     

O. Tanimura 《Physics letters. [Part B]》1980,90(3):204-208

It is shown that the gross structure of the fusion cross section of the ¹⁶O + ¹⁶O collision is well reproduced by a simple coupled channel method including only elastic and inelastic ¹⁶O + ¹⁶O(3^?) channels, as well as the excitation functions of the elastic and total inelastic ¹⁶O + ¹⁶O(3^?) cross sections.     

18.

Phase-shift analysis of ¹⁶O + ¹⁶O elastic scattering data     

W. Tiereth  Z. Basrak  N. Bischof  H. Fröhlich  H. Voit 《Nuclear Physics A》1985,440(1):143-151

A phase-shift analysis of precisely measured elastic ¹⁶O + ¹⁶O data has been carried out in order to establish the existence of molecular resonances between E_c.m = 15.5 and 18 MeV and to investigate the possible structure of these resonances.     

19.

Microscopic study of the ¹²C + ¹⁶O system     

D. Baye 《Nuclear Physics A》1976,272(2):445-465

An angular momentum projected microscopic calculation is performed for the ¹²C + ¹⁶O system with an effective nuclear force and the exact Coulomb interaction. The ¹²C wave function is projected on a 0⁺ state. Parametrizations of the Coulomb interaction between the nuclei are fitted. The L-projected energy curves present a quite complicated structure especially for the negative parity states. The role played by critical angular momenta is put into evidence. A generator coordinate calculation gives several bands of bound, quasibound and virtual states. Excellent agreement in energy and angular momentum is obtained with the 13.7 MeV (J = 9), 19.7 MeV (J = 14), 22.7 MeV (J = 15) and other resonances.     

20.

Microscopic study of elastic ¹²C+¹⁶O scattering     

D. Baye  P.-H. Heenen 《Nuclear Physics A》1977,283(1):176-188

The L=0 to 17 phase shifts are calculated microscopically for elastic ¹²C+¹⁶O scattering with a generator coordinate method. The experimental resonances are shown to belong to four different bands. Interpretations and spin assignments are suggested for several recently observed anomalies. A spin J=15 seems likely for the 22.8 MeV resonance. A missing J=13 resonance should be searched for between 17 and 18 MeV.     

	H212C17O	H213C17O
$\text{A}$	281 965.0 (30)	281 987.3 (19)
$\text{B}$	37 812.287(45)	36 776.790(25)
$\text{C}$	33 214.523(31)	32 412.920(19)

The infrared spectra of 12C32S, 12C34S, 13C32S,and 12C33S

Using a tunable diode laser spectrometer, the infrared absorption spectra of four isotopic species of carbon monosulfide have been observed in the positive column of a dc discharge of CS₂ and Ar. The wavenumbers of 115 vibration-rotation transitions between 1180.5 and 1266.1 cm^?1 have been measured. These lines were assigned to the 1-0, 2-1, 3-2, and 4-3 bands of ¹²C³²S, the 1-0 and 2-1 bands of ¹²C³⁴S and ¹³C³²S, and the 1-0 band of ¹²C³³S. These new data have been combined with the previous infrared and microwave results to determine Dunham coefficients (Y_ij), the Dunham potential expansion constants (a₀,a₁,a₂,a₃, and a₄), and the classical turning points by the RKR method.     

Low energy fusion of 12C + 12C and 16O + 16O systems

The adiabatic time-dependent Hartree-Fock method (ATDHF) is applied to the calculation of low energy fusion of ¹²C + ¹²C and ¹⁶O + ¹⁶O systems. The energy dependence of the results is in good agreement with experiment, while the order of magnitude is not correct. It is shown that the dynamical effects included in ATDHF are very important and cannot be neglected at the energies of astrophysical interest.     

Helium and self-broadening in the first and second overtone bands of 12C16O

The pressure broadening coefficients for rotation-vibration lines of J states up to 22 in the 2-0 band and J states up to 20 in the 3-0 band of pure CO and HeCO mixtures were measured. The data were obtained at room temperature utilizing a Fourier transform spectrometer and various cells, including a 113-m White cell. These data exhibit little change with increasing vibrational level, and in the case of helium broadening, only slight J dependence.     

Determination of laser line frequencies and vibrational-rotational constants of the 12C18O2, 13C16O2, and 13C18O2 isotopes from measurements of CW beat frequencies with fast HgCdTe photodiodes and microwave frequency counters

The frequencies of ¹²C¹⁸O₂, ¹³C¹⁶O₂, and ¹³C¹⁸O₂ isotope lasers have been measured to better than 3 MHz (0.0001 cm^?1) by comparing with a ¹²C¹⁶O₂ reference laser. Heterodyne techniques were used to generate 139 difference frequencies in a liquid nitrogen cooled HgCdTe photodiode. Microwave frequency counter measurements of the difference frequencies were then used to calculate new values for the band centers and rotational constants of the rare isotopes. Procedures to achieve further improvements are discussed.     

Absolute frequency measurements of N2O laser transitions

The absolute frequencies of 33 P- and R-branch lines of the N₂O, 00°1–10°0 laser band have been measured by heterodyning with known CO₂ laser frequencies of the 00°1 – 10°0 band in a tungsten-nickel diode. These measurements were used to calculate more precise values for the band centre and for the rotational constants.     

The ν3 band of 16O12C34S and 16O13C34S

The ν₃ fundamental of OCS has been measured with a resolution of about 0.03 cm^?1 for the isotopic species ¹⁶O¹²C³⁴S and ¹⁶O¹³C³⁴S. The associated transition 01¹1-01¹0 has also been measured. The transition 10⁰1-00⁰0 is also reported for the ¹⁶O¹²C³⁴S species.     

Radiative pion capture in 12C and 16O

Radiative pion capture in ¹²C and ¹⁶O is investigated. An effective interaction Hamiltonian based upon the CGLN theory is employed. Capture rates in ¹²C and ¹⁶O from Is and 2p pionic orbits are calculated by using the nuclear model of Kamimura, Ikeda and Arima for the odd parity states of ¹²C, and that of Walker with strong ground state correlations, for the odd parity states of ¹⁶O. The results are compared with those of the 1p-1h nuclear model under the Tamm-Dancoff and random phase approximations of Gillet and Vinh Mau. Detailed examinations are made for the transitions to low-lying states with 1⁺ and 2⁺ for ¹²C and with 1^?, 2^? and 3^? for ¹⁶O by using the Cohen-Kurath and the Walker models, respectively. The results are in good agreement with the recent experimental data from Berkeley.     

Improved rovibrational constants and frequency tables for the normal laser bands of 12C16O2

New frequency difference measurements between Doppler-free stabilized laser lines in the 9.4- and 10.4-μm bands of ¹²C¹⁶O₂, including high-J and across-the-band-center measurements, have made significant improvements in the rovibrational constants. The absolute frequencies were referred to the methane stabilized 3.39-μm HeNe laser. Frequency tables generated from these constants have absolute uncertainties of less than two parts in 10¹⁰ and are about a factor of 10 better than older tables. In addition, the laser lines P_I(50) in ¹³C¹⁶O₂ and R_II(26) in ¹³C¹⁸O₂, which were used as reference lines in recent visible laser frequency measurements, were also measured to about the same accuracy.     

16O(p,α0)13N cross-section measurements

Total cross sections for the ${}^{16}\text{O}\text{(}\text{p}\text{, α}{}_0\text{)}{}^{13}\text{N}$ reaction have been measured by observation of the positron decay of the residual ¹³N nuclei. These cross sections, covering the c.m. energy range 5.4 ≦ E ≦ 9.9 MeV, allow determination of reaction rates of astrophysical interest at temperatures in the neighborhood of 4 × 10⁹°K.     

Phase-shift analysis of 16O + 16O elastic scattering

A phase-shift analysis has been carried out for ¹⁶O + ¹⁶O elastic scattering, resulting in unambiguous values for the reflection coefficients in the energy range of the first gross structure of the 90° excitation function, and answering some of the questions still open regarding the calculations existing so far.     

The infrared spectrum of 12C32S and 12C34S

The 2-0 vibration-rotation bands of ¹²C³²S and ¹²C³⁴S near 2530 cm^?1 have been measured with a high resolution spectrometer. The spectroscopic constants for these bands are given, as well as an improved set of Dunham coefficients for the X¹Σ⁺ state of ¹²C³²S.     

A precise study of the rotational spectrum of formaldehyde H212C17O and H213C17O

The pure rotational spectra of H₂¹²C¹⁷O and H₂¹³C¹⁷O have been investigated in the frequency region between 8 and 360 GHz in the ground vibrational state. For both isotopic species the ¹⁷O nuclear quadrupole coupling constants and spin-rotation constants have been obtained. From both Q- and R-branch transitions a set of rotational constants and several distortion constants could be derived employing Watson's formalism in A reduction. The obtained rotational constants are in Megahertz:

Fusion cross section of the 16O + 16O collision

It is shown that the gross structure of the fusion cross section of the ¹⁶O + ¹⁶O collision is well reproduced by a simple coupled channel method including only elastic and inelastic ¹⁶O + ¹⁶O(3^?) channels, as well as the excitation functions of the elastic and total inelastic ¹⁶O + ¹⁶O(3^?) cross sections.     

Phase-shift analysis of 16O + 16O elastic scattering data

A phase-shift analysis of precisely measured elastic ¹⁶O + ¹⁶O data has been carried out in order to establish the existence of molecular resonances between E_c.m = 15.5 and 18 MeV and to investigate the possible structure of these resonances.     

Microscopic study of the 12C + 16O system

An angular momentum projected microscopic calculation is performed for the ¹²C + ¹⁶O system with an effective nuclear force and the exact Coulomb interaction. The ¹²C wave function is projected on a 0⁺ state. Parametrizations of the Coulomb interaction between the nuclei are fitted. The L-projected energy curves present a quite complicated structure especially for the negative parity states. The role played by critical angular momenta is put into evidence. A generator coordinate calculation gives several bands of bound, quasibound and virtual states. Excellent agreement in energy and angular momentum is obtained with the 13.7 MeV (J = 9), 19.7 MeV (J = 14), 22.7 MeV (J = 15) and other resonances.     

Microscopic study of elastic 12C+16O scattering

The L=0 to 17 phase shifts are calculated microscopically for elastic ¹²C+¹⁶O scattering with a generator coordinate method. The experimental resonances are shown to belong to four different bands. Interpretations and spin assignments are suggested for several recently observed anomalies. A spin J=15 seems likely for the 22.8 MeV resonance. A missing J=13 resonance should be searched for between 17 and 18 MeV.