{"created":"2023-06-20T13:20:11.131702+00:00","id":190,"links":{},"metadata":{"_buckets":{"deposit":"134b769f-e3ed-4d1f-b9c8-2dc23ec29763"},"_deposit":{"created_by":1,"id":"190","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"190"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00000190","sets":["2:427:9"]},"author_link":["7743","7745","7744"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"荒木, 光典"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"アラキ, ミチノリ"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"1999-03-24"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"        Over one hundred molecular species have been detected in interstellar space by radio astronomical observations. It is generally accepted that the most abundant molecules in dark clouds have been already detected. These interstellar molecules are mainly produced by ion-molecule reactions, which are uniquely efficient in the interstellar physical conditions of low temperature and low density. This makes molecular ions extremely important intermediates in the interstellar chemistry even at very small abundances. Since detection of ions in interstellar space has been extremely limited, it is thought that they have not accumulated sufficient observational information to explain the reaction scheme. Physical and chemical processes in the interstellar space can be studied by using spectral lines of the molecular ions, and laboratory microwave spectroscopy is a powerful tool for supplying precise transition frequencies of the ions to radio astronomy. However, laboratory measurements are not easy because of the difficulty in producing sufficient concentrations of ions. Development of efficient production methods for molecular ions will make it possible to observe many more of them by microwave spectroscopy.\n         Several interstellar molecules have been found to have large D/H ratios enhanced by factors of 10<SUP>3</SUP>- 10<SUP>4</SUP> over the primordial cosmic D/H ratio of ? 1.5 X 10<SUP>-5</SUP>.  For example, the abundance ratio of the deuterated species to HCN, [DCN]/ [HCN], is found to be 0.023 in the dark cloud, Taurus Molecular Cloud (TMC-1). This enhancement is called \"deuterium enrichment.\" The degree of the deuterium enrichment is determined by physical conditions and related reactions in interstellar clouds. In other words the deuterium enrichment is generally a good probe to study the reaction scheme in space. As a result laboratory microwave spectroscopic studies of deuterated species are important in astronomy as well as in molecular spectroscopy.  He has studied several deuterated molecular ions related to interstellar phenomena.\n\nMicrowave spectra of D<SUB>3</SUB>O<SUP>+</SUP> and D<SUB>3</SUB>S<SUP>+</SUP>\n        The hydronium ion H<SUB>3</SUB>O<SUP>+</SUP> is a precursor to fundamental hydroxy interstellar molecules. For example, OH and H<SUB>2</SUB>O are generated by an exothermic recombination of electrons with H<SUB>3</SUB>O<SUP>+</SUP>. Similarly H<SUB>2</SUB>DO<SUP>+</SUP> is a precursor to OD and HDO and is generated by a series of ion-molecule reactions starting from a reaction of O with H<SUB>2</SUB>D<SUP>+</SUP>. H<SUB>2</SUB>D<SUP>+</SUP> is a key molecule in the interstellar deuterium fractionation processes. Therefore, the interstellar [H<SUB>2</SUB>DO<SUP>+</SUP>]/[H<SUB>3</SUB>O<SUP>+</SUP>] ratios are very important information for an understanding of the fractional reaction scheme in molecular clouds. Although the inversion-rotation spectrum of H<SUB>3</SUB>O<SUP>+</SUP> is well known, prediction of H<SUB>2</SUB>DO<SUP>+</SUP> is not easy because it requires a precise molecular structure of H<SUB>3</SUB>O<SUP>+</SUP> and a precise potential for inversion motion of H<SUB>3</SUB>O<SUP>+</SUP>. So, to obtain an improved the molecular structure and potential of H<SUB>3</SUB>O<SUP>+</SUP>, he studied the inversion-rotation spectrum of its fully deuterated species D<SUB>3</SUB>O<SUP>+</SUP>.\n        Microwave spectra of the ions were observed using a microwave spectrometer at the Institute for Molecular Science. The spectrometer was a 100 kHz source- modulated system. Microwave radiation was generated with a combination of frequency multipliers and klystrons. An InSb photoconductive detector cooled by liquid helium was used to measure the power of microwave radiation. A free space discharge cell was cooled by circulating liquid nitrogen through a copper tube soldered on a copper sheet covering the glass cell. \n       After several trials he found that deuterated species of H<SUB>3</SUB>O<SUP>+</SUP> were efficiently produced by a hollow-cathode dc-glow discharge in a mixture of D<SUB>2</SUB> and D<SUB>2</SUB>O in a 2 m length and 10 cm diameter free-space absorption cell. The length of the hollow cathode was 1.3 m. The production of the ions in the cell is increased by the hollow cathode effect. \n       Fifty three P- and Q-branch transitions between the lowest pair of levels of the inversion motion were precisely measured in the frequency region of 220 to 565 GHz. An analysis of the observed spectral lines yielded molecular constants for the upper (0<SUP>-</SUP>) and lower (0<SUP>+</SUP>) levels in the inversion motion. The inversion splitting was accurately determined to be 15.35550086(147) cm<SUP>-1</SUP>, where the number in parentheses denotes one standard deviation of the fit. Combined with IR data, the inversion splitting of D<SUB>3</SUB>O<SUP>+</SUP> for the v<SUB>2</SUB> inversion state was determined to be 191.38874(98) cm<SUP>-1</SUP>. As a total, two inversion splittings were precisely determined by microwave spectroscopy and are important information for a proper understanding of the inversion potential of H<SUB>3</SUB>O<SUP>+</SUP>. Potential function parameters can be revised using the two inversion splittings. Furthermore, a reliable inversion splitting of H<SUB>2</SUB>DO<SUP>+</SUP> can now be estimated from the new potential function parameters and used to predict transition frequencies of H<SUB>2</SUB>DO<SUP>+</SUP>. \n       The average structures (r<SUB>z</SUB> structure) of H<SUB>3</SUB>O<SUP>+</SUP> and D<SUB>3</SUB>O<SUP>+</SUP>, that is, averaged for zero point motion in the ground vibrational state, were derived from their averaged rotational constants. The results are as follows: for D<SUB>3</SUB>O<SUP>＋</SUP> (0<SUP>+</SUP>) ; r<SUB>z</SUB> = 0.98392(152) Å, θ<SUB>z</SUB> = 113.62(65)°, and for D<SUB>3</SUB>O<SUP>+</SUP> (0<SUP>-</SUP>) ; r<SUB>z</SUB> = 0.98510(152)Å,θ<SUB>z</SUB> = 112.94(65)° where r is O-D bond length and θ D-O-D bond angle. The equilibrium structure (r<SUB>e</SUB> structure) of H<SUB>3</SUB>O<SUP>+</SUP>, a hypothetical structure of the potential, was determined from the r<SUB>z</SUB> structures of H<SUB>3</SUB>O<SUP>+</SUP> and D<SUB>3</SUB>O<SUP>+</SUP> by extrapolations. The r<SUB>e</SUB> structure was obtained to be r<SUB>e</SUB> = 0.9780(59) Å,θ<SUB>e</SUB>. = 112.8(25)°. As a result, he was able to estimate the rotational constants of H<SUB>2</SUB>DO<SUP>+</SUP> from the structures of H<SUB>3</SUB>O<SUP>+</SUP> and D<SUB>3</SUB>O<SUP>+</SUP>, which were used to predict a spectral pattern of H<SUB>2</SUB>DO<SUP>+</SUP>. \n        In addition, he succeeded in observing the D<SUB>3</SUB>S<SUP>+</SUP> ion generated by the hollow- cathode discharge. The J= 1-0 to 4-3 spectral lines of D<SUB>3</SUB>S<SUP>+</SUP> were measured in the 152 - 610 GHz region. The molecular constants were determined from the measured frequencies. The precise molecular structure of H<SUB>3</SUB>S<SUP>+</SUP> and D<SUB>3</SUB>S<SUP>+</SUP> was derived from their rotational constants. \n\nMicrowave spectra of HCNH<SUP>+</SUP> and its deuterated species \n       The method of a magnetically confined dc-glow discharge was employed to efficiently produce a protonated ion HCNH<SUP>+</SUP>, whose concentration was enhanced due to a lengthening of ion-rich negative glow and an increase of ionizing electron density. Around the absorption cell is wound a solenoid coil of enameled wire. The magnetic field was generated to confine the discharge plasma. The HCNH<SUP>+</SUP> and its isotopic species were produced by the discharge in HCN and/or DCN at around -120℃. The optimum magnetic field was about one hundred Gauss. \n       The interstellar protonated hydrogen cyanide ion, HCNH<SUP>+</SUP>, is mainly produced by reactions of HNC and HCN with H<SUB>3</SUB><SUP>+</SUP> HCN<SUP>+</SUP> or H<SUB>3</SUB>O<SUP>+</SUP>, and is also considered to be a precursor of HNC, HCN and CN in dark molecular clouds. Detection of HCND<SUP>+</SUP> may give information about the deuterium fractionation in molecular clouds. The pure rotational transitions of HCNH<SUP>+</SUP>, and its isotopic species, HCND<SUP>+</SUP> and DCND<SUP>+</SUP>, were measured in the 107 - 482 GHz region. The rotational constant B<SUB>0</SUB> and the centrifugal distortion constant D<SUB>0</SUB> for each ion were precisely determined by a least- squares fitting to the observed spectral lines. The observed rotational transition frequencies and the predicted ones are accurate within about 30 to 40 kHz and are useful for astronomical searches of HCNH<SUP>+</SUP> and HCND<SUP>+</SUP>.","subitem_description_type":"Other"}]},"item_1_description_18":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第374号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"数物科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"07 構造分子科学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"1998"}]},"item_1_version_type_23":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_ab4af688f83e57aa","subitem_version_type":"AM"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"ARAKI, Michinori","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲374_要旨.pdf","filesize":[{"value":"574.9 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨 / Abstract, Screening Result","url":"https://ir.soken.ac.jp/record/190/files/甲374_要旨.pdf"},"version_id":"c2bb0c3f-2533-4e9f-9400-882775284e26"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲374_本文.pdf","filesize":[{"value":"10.0 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文 / Thesis","url":"https://ir.soken.ac.jp/record/190/files/甲374_本文.pdf"},"version_id":"e4213fed-d8bd-4737-8436-e98125bdbdff"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Microwave spectroscopy of deuterated molecular ions and structures of pyramidal XY3 molecules","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Microwave spectroscopy of deuterated molecular ions and structures of pyramidal XY3 molecules"},{"subitem_title":"Microwave spectroscopy of deuterated molecular ions and structures of pyramidal XY3 molecules","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["9"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"190","relation_version_is_last":true,"title":["Microwave spectroscopy of deuterated molecular ions and structures of pyramidal XY3 molecules"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T14:59:35.598051+00:00"}