I. Spectroscopic evidence for slow vibrational relaxation in excited electronic states of diatomics in rare gas solids. II. Static crystal field effects in the electronic spectra of isotopically mixed benzene crystals

Part I

Studies of vibrational relaxation in excited electronic states of simple diatomic molecules trapped in solid rare-gas matrices at low temperatures are reported. The relaxation is investigated by monitoring the emission intensity from vibrational levels of the excited electronic state to vibrational levels of the ground electronic state. The emission was in all cases excited by bombardment of the doped rare-gas solid with X-rays.

The diatomics studied and the band systems seen are: N₂, Vegard-Kaplan and Second Positive systems; O₂, Herzberg system; OH and OD, A ²Σ⁺ - X²II_i system. The latter has been investigated only in solid Ne, where both emission and absorption spectra were recorded; observed fine structure has been partly interpreted in terms of slightly perturbed rotational motion in the solid. For N₂, OH, and OD emission occurred from v' > 0, establishing a vibrational relaxation time in the excited electronic state of the order, of longer than, the electronic radiative lifetime. The relative emission intensity and decay times for different v' progressions in the Vegard-Kaplan system are found to depend on the rare-gas host and the N₂ concentration, but are independent of temperature in the range 1.7°K to 30°K.

Part II

Static crystal field effects on the absorption, fluorescence, and phosphorescence spectra of isotopically mixed benzene crystals were investigated. Evidence is presented which demonstrate that in the crystal the ground, lowest excited singlet, and lowest triplet states of the guest deviate from hexagonal symmetry. The deviation appears largest in the lowest triplet state and may be due to an intrinsic instability of the ³B_1u state. High resolution absorption and phospho- rescence spectra are reported and analyzed in terms of site-splitting of degenerate vibrations and orientational effects. The guest phosphorescence lifetime for various benzene isotopes in C₆D₆ and sym-C₆H₃D₃ hosts is presented and discussed.

I. Electronic states of heavily-doped molecular crystals--naphthalene. I. Theoretical. II. Experimental. II. Lowest singlet and triplet excited states of pyrazine

PART I

The energy spectrum of heavily-doped molecular crystals was treated in the Green’s function formulation. The mixed crystal Green’s function was obtained by averaging over all possible impurity distributions. The resulting Green’s function, which takes the form of an infinite perturbation expansion, was further approximated by a closed form suitable for numerical calculations. The density-of-states functions and optical spectra for binary mixtures of normal naphthalene and deuterated naphthalene were calculated using the pure crystal density-of-state functions. The results showed that when the trap depth is large, two separate energy bands persist, but when the trap depth is small only a single band exists. Furthermore, in the former case it was found that the intensities of the outer Davydov bands are enhanced whereas the inner bands are weakened. Comparisons with previous theoretical calculations and experimental results are also made.

PART II

The energy states and optical spectra of heavily-doped mixed crystals are investigated. Studies are made for the following binary systems: (1) naphthalene-h₈ and d₈, (2) naphthalene--h₈ and αd₄, and (3) naphthalene--h₈ and βd₁, corresponding to strong, medium and weak perturbations. In addition to ordinary absorption spectra at 4˚K, band-to-band transitions at both 4˚K and 77˚K are also analyzed with emphasis on their relations to cooperative excitation and overall density-of-states functions for mixed crystals. It is found that the theoretical calculations presented in a previous paper agree generally with experiments except for cluster states observed in system (1) at lower guest concentrations. These features are discussed semi-quantitatively. As to the intermolecular interaction parameters, it is found that experimental results compare favorably with calculations based on experimental density-of-states functions but not with those based on octopole interactions or charge-transfer interactions. Previous experimental results of Sheka and the theoretical model of Broude and Rashba are also compared with present investigations.

PART III

The phosphorescence, fluorescence and absorption spectra of pyrazine-h₄ and d₄ have been obtained at 4˚K in a benzene matrix. For comparison, those of the isotopically mixed crystal pyrazine-h₄ in d₄ were also taken. All these spectra show extremely sharp and well-resolved lines and reveal detailed vibronic structure.

The analysis of the weak fluorescence spectrum resolves the long-disputed question of whether one or two transitions are involved in the near-ultraviolet absorption of pyrazine. The “mirror-image relationship” between absorption and emission shows that the lowest singlet state is an allowed transition, properly designated as ¹B_3u ← ¹A_1g. The forbidden component ¹B_2g, predicted by both “exciton” and MO theories to be below the allowed component, must lie higher. Its exact location still remains uncertain.

The phosphorescence spectrum when compared with the excitation phosphorescence spectra, indicates that the lowest triplet state is also symmetry allowed, showing a strong 0-0 band and a “mirror-image relationship” between absorption and emission. In accordance with previous work, the triplet state is designated as ³B_3u.

The vibronic structure of the phosphorescence spectrum is very complicated. Previous work on the analysis of this spectrum all concluded that a long progression of v_6a exists. Under the high resolution attainable in our work, the supposed v_6a progression proves to have a composite triplet structure, starting from the second member of the progression. Not only is the v_9a hydrogen-bending mode present as shown by the appearance of the C-D bending mode in the d₄ spectrum, but a band of 1207 cm^-1 in the pyrazine in benzene system and 1231 cm^-1 in the mixed crystal system is also observed. This band is assigned as 2v_6b and of a_1g symmetry. Its anonymously strong intensity in the phosphorescence spectrum is interpreted as due to the Fermi resonance with the 2v_6a and v_9a band.

To help resolve the present controversy over the crystal phosphorescence spectrum of pyrazine, detailed vibrational analyses of the emission spectra were made. The fluorescence spectrum has essentially the same vibronic structure as the phosphorescence spectrum.

Report of the Inter-American Tropical Tuna Commission for the year 1972

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967 Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 12, 1968. The Commission held three meetings in 1972: the 26th meeting in Tokyo, Japan, on January 6, 7 and 13; the 27th meeting in Panama, Republic of Panama, on November 7, 8 and 11; and the 28th meeting in San Diego, California, on December 20. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968. La Comisión celebró tres reuniones en 1972: la XXVI reunion en Tokio, Japón, el 6, 7 Y 13 de enero; la XXVII reunión en Panamá, República de Panamá, el 7, 8 Y 11 de noviembre; y la XVIII reunión en San Diego, California, el 20 de diciembre. (PDF contains 166 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1973

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967 Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 12, 1968. The Commission held its 29th meeting on November 12, 13, 14 and 16, 1973, in Washington, D. C., U. S. A. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968. La Comisión celebró su XXIX Reunión e112, 13,14 Y16 de Noviembre 1973, en Washington, D. C., E. U. A. (PDF contains 150 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1974

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967, Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 21,1968. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968.(PDF contains 170 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1975

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967, Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 21,1968. The Commission held two meetings in 1975, its 31st n1eeting in San Diego, California, U.S.A., March 3 and 5, and its 32nd meeting in Paris, France, October 13, 14 and 17, and in Washington D.C., U.S.A., December 18. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968. La Comisión celebró dos reuniones en 1975, la XXXI reunión en San Diego, California (E.U.A.) del 3 al 5 de marzo, y la XXXII reunión en París, Francia el 13, 14 Y 17 de octubre (primera parte) y en Washington D.C. (E.U.A.) el 18 de diciembre (segunda parte). (PDF contains 176 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1976

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967, Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 21,1968The Commission held its 33rd meeting in Managua, Nicaragua, during October 11-14. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968. La Comisión celebró su XXXIII reunión en Managua, Nicaragua del 11 al 14 de octubre. (PDF contains 180 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1977

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967, Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 21,1968. The Commission held two meetings in 1977, the 34th from June 27 to 29 in San Diego, California, and the 35th on October 17 and 18 in Mexico City. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968. La Comisión celebró dos reuniones en 1977, la XXXIV del 27 al 29 de junio en San Diego (California) y la XXXV del 17 al 18 de octubre en ciudad de México. (PDF contains 156 pages).

Report of the Inter-American Tropical Tuna Commission for the year 1978

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision the Republic of Panama adhered in 1953, the Republic of Ecuador in 1961, the United Mexican States in 1964, Canada in 1968 and Japan in 1970. In 1967, Ecuador gave notice of her intent to withdraw from the Commission, and her withdrawal became effective on August 21,1968. The Commission held two meetings in 1977, the 34th from June 27 to 29 in San Diego, California, and the 35th on October 17 and 18 in Mexico City. The Commission adjourned its 35th meeting, held in Mexico City on October 17, and 18, 1977, without agreeing to a resolution for the conservation of yellowfin during 1978. SPANISH: La Comisión Interamericana del Atún Tropical está bajo la autoridad y dirección de una convención la cual fue originalmente formada por la República de Costa Rica y los Estados Unidos de América. La Convención, vigente desde 1950, está abierta a la afiliación de otros gobiernos cuyos nacionales pesquen atún en el Pacífico oriental tropical. Bajo esta medida la República de Panamá se afilió en 1953, la República del Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968 y el Japón en 1970. En 1967, el Ecuador anunció su intención de retirarse de la Comisión y la renuncia se hizo efectiva el 21 de agosto de 1968. La Comisión celebró dos reuniones en 1977, la XXXIV del 27 al 29 de junio en San Diego (California) y la XXXV del 17 al 18 de octubre en ciudad de México. La Comisión clausuró su XXXV reunión, celebrada en ciudad de México del 17 al 18 de octubre de 1977, sin acordar una resolución para la conservación del atún aleta amarilla en 1978. (PDF contains 164 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1979

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision Panama adhered in 1953, Ecuador in 1961, the United Mexican States in 1964, Canada in 1968, Japan in 1970 and France and Nicaragua in 1973. Ecuador withdrew from the Commission in 1968, Mexico in 1978, and Costa Rica in 1979. SPANISH: La Comisión Interamericana del Atún Tropical funciona bajo la autoridad y dirección de un convenio establecido originalmente por la República de Costa Rica y los Estados Unidos de América. El convenio vigente desde 1950, está abierto a la afiliación de otros gobiernos cuyos ciudadanos pescan atún en el Pacífico oriental tropical. Bajo esta estipulación, Panamá se afilió en 1953, Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968, Japón en 1970, Francia y Nicaragua en 1973. Ecuador se retiró de la Comisión en 1968, México en 1978 y Costa Rica en 1979. Como se informó en el informe anual de la Comisión de 1978, la XXXVI reunión de la Comisión, convocada en Tokio (Japón) del 16 al 18 de octubre de 1978, fue suspendida sin haberse adoptado ninguna acción para fijar una cuota de atún aleta amarilla en 1979.(PDF contains 228 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1980

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision Panama adhered in 1953, Ecuador in 1961, the United Mexican States in 1964, Canada in 1968, Japan in 1970 and France and Nicaragua in 1973. Ecuador withdrew from the Commission in 1968, Mexico in 1978, and Costa Rica in 1979. SPANISH: La Comisión Interamericana del Atún Tropical funciona bajo la autoridad y dirección de un convenio establecido originalmente por la República de Costa Rica y los Estados Unidos de América. El convenio vigente desde 1950, está abierto a la afiliación de otros gobiernos cuyos ciudadanos pescan atún en el Pacífico oriental tropical. Bajo esta estipulación, Panamá se afilió en 1953, Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968, Japón en 1970, Francia y Nicaragua en 1973. Ecuador se retiró de la Comisión en 1968, México en 1978 y Costa Rica en 1979. Como se informó en el informe anual de la Comisión de 1978, la XXXVI reunión de la Comisión, convocada en Tokio (Japón) del 16 al 18 de octubre de 1978, fue suspendida sin haberse adoptado ninguna acción para fijar una cuota de atún aleta amarilla en 1979. (PDF contains 236 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1981

ENGLISH: The Inter-American Tropical Tuna Commission operates under the authority and direction of a convention originally entered into by the Republic of Costa Rica and the United States of America. The convention, which came into force in 1950, is open to adherence by other governments whose nationals fish for tropical tunas in the eastern Pacific Ocean. Under this provision Panama adhered in 1953, Ecuador in 1961, the United Mexican States in 1964, Canada in 1968, Japan in 1970 and France and Nicaragua in 1973. Ecuador withdrew from the Commission in 1968, Mexico in 1978, and Costa Rica in 1979. The Commission's 39th meeting was held in Paris, France, on October 19 to 21, 1981. SPANISH: La Comisión Interamericana del Atún Tropical funciona bajo la autoridad y dirección de un convenio establecido originalmente por la República de Costa Rica y los Estados Unidos de América. El convenio vigente desde 1950, está abierto a la afiliación de otros gobiernos cuyos ciudadanos pescan atún en el Pacífico oriental tropical. Bajo esta estipulación, Panamá se afilió en 1953, Ecuador en 1961, los Estados Unidos Mexicanos en 1964, Canadá en 1968, Japón en 1970, Francia y Nicaragua en 1973. Ecuador se retiró de la Comisión en 1968, México en 1978 y Costa Rica en 1979. Como se informó en el informe anual de la Comisión de 1978, la XXXVI reunión de la Comisión, convocada en Tokio (Japón) del 16 al 18 de octubre de 1978, fue suspendida sin haberse adoptado ninguna acción para fijar una cuota de atún aleta amarilla en 1979. La XXXIX reunión de la Comisión fue celebrada en París (Francia) del 19 al 21 de octubre de 1981. (PDF contains 304 pages.)