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4. Analiz

4.1. Obshie ocenki

Analiz vliyaniya oshibok opredeleniya konstant himicheskih reakcii na rezul'taty modelirovaniya proizvodilsya sleduyushim obrazom.

Dlya kazhdogo soedineniya byli opredeleny znacheniya minimal'nogo i maksimal'nogo logarifmov ravnovesnyh obilii po otnosheniyu k vodorodu. Posle etogo poluchennye intervaly byli razbity na 100 ravnyh chastei i poschitano kolichestvo modelei, dlya kotoryh znachenie sootvetstvuyushego obiliya popalo v kazhdyi iz intervalov. Dlya vseh soedinenii byli postroeny sootvetstvuyushie gistogrammy. Na risunkah 1, 2, 3, 4 i 5 predstavleny gistogrammy dlya HCN, HC3N i HC5N, a takzhe dlya otnoshenii HCN/ HC3N i HC3N/ HC5N. Eti sootnosheniya budut rassmotreny podrobno dalee.

Vse 384 himicheskih soedineniya byli razbity na 6 grupp po ustoichivosti znacheniya ih obilii k var'irovaniyu konstant skorostei. Osnovoi deleniya stala shirina gistogrammy na vysote, sootvetstvuyushei polovine znacheniya maksimuma gistogrammy. Raspredelenie soedinenii po gruppam predstavleno v tablice 3.

V 1-yu gruppu ustoichivosti popalo 11 himicheskih elementov i soedinenii. Preobladayut himicheski neaktivnye elementy i soedineniya. Odnako est' i isklyucheniya. Samoe yarkoe himicheski aktivnyi ion H3O+.

Absolyutnoe bol'shinstvo iz 384 soedinenii popali vo 2, 3 i 4 gruppy (36, 119 i 153 soedineniya sootvetstvenno). Prichem, bol'shaya chast' obil'nyh v mezhzvezdnoi srede soedinenii okazalis' vo 2 i 3 gruppah (CO, CS, H2CO, NH3, CH3OH, H2O, CH4 i drugie).

Odnako nekotorye nablyudaemye soedineniya, v chastnosti, cianopoliiny, okazalis' v 4 gruppe ustoichivosti.

V celom, horosho proslezhivaetsya tendenciya popadaniya bolee slozhnyh i tyazhelyh soedinenii v gruppu ustoichivosti s bol'shim nomerom. Fizicheskim ob'yasneniem etogo, po-vidimomu, yavlyaetsya to, chto k obrazovaniyu bolee slozhnyh (sostoyashih iz bol'shogo chisla atomov) soedinenii privodyat bolee dlinnye cepochki himicheskih reakcii, nezheli k obrazovaniyu prostyh soedinenii. Oshibki opredeleniya konstant himicheskih reakcii v dlinnyh cepochkah, peremnozhayas' mezhdu soboi, sushestvenno snizhayut tochnost', s kotoroi poluchaetsya obilie konechnogo produkta rassmatrivaemoi slozhnoi molekuly. V 5, 6 i 7 gruppah nahodyatsya, preimushestvenno nenablyudaemye v nastoyashee vremya slozhnye molekuly s dlinnymi uglerodnymi cepochkami, obrazuyushiesya v konce slozhnoi cepochki himicheskih reakcii.

V mezhzvezdnoi srede nablyudaetsya bol'shoe kolichestvo otnositel'no legkie molekuly. Tochnost' opredelenii ih obilii iz nablyudatel'nyh dannyh sostavlyaet, kak pravilo, 1-1,5 poryadka. Takim obrazom, mozhno sdelat' vyvod, chto vliyanie oshibok opredeleniya konstant himicheskih reakcii nekritichno dlya modelirovaniya obilii legkih molekul, imeyushih dostatochno prostuyu strukturu.

V to zhe vremya, vliyanie oshibok opredeleniya konstant himicheskih reakcii sushestvenno bol'she dlya molekul s uglerodnymi cepochkami i bystro narastaet s uvelicheniem dliny cepochki. Dlya molekul s 4-atomnoi uglerodnoi cepochkoi oshibka sostavlyaet poryadka 2 poryadkov, no dlya 8-9-atomnyh prevyshaet 3.5 poryadka, chto sushestvenno dlya lyubyh modelei.

 

4.2. Vliyanie oshibok konstant reakcii na opredelenie vozrasta oblakov.

Kak bylo skazano vo vvedenii, oshibki opredeleniya obilii soedinenii i ih otnoshenii mogut sushestvenno otrazhat'sya na nashih znaniyah o fizicheskih svoistvah rassmatrivaemyh ob'ektov. Horoshei illyustraciei etogo utverzhdeniya yavlyaetsya zavisimost' vozrasta molekulyarnyh oblakov, poluchaemaya iz otnoshenii obilii cianopoliinov, ot oshibki modelirovaniya etih otnoshenii.

Na risunkah 1, 2, 3 i 4 pokazano raspredelenie obilii HCN, HC3N i HC5N molekul, ispol'zuyushihsya dlya ocenki vozrasta, - v nashih modelyah.


Tablica 3. Raspredelenie himicheskih elementov i soedinenii po gruppam tochnosti.

1

Δ Log Ab

< 0.25

2

Δ Log Ab

0.25 0.5

3

Δ Log Ab

0.5 1.0

4

Δ Log Ab

1.0 2.0

5

Δ Log Ab

2.0 3.0

6

Δ Log Ab

3.0 4.0

H2

He

P

Cl

Na+

SO

Mg+

O2

N2

Fe+

H3O+

H

N

O

Na

Mg

Fe

H+

He+

NH3+

N2+

NH3

CS

PO

HCl

H2+

HCO+

NH2+

CO+

N2H+

HPO+

H2O

HeH+

NH+

H2O+

HOC+

HCS+

SO+

H3+

OH+

NH4+

O2+

O+

Si+

SiO+

SiOH+

PO+

C

S

Si

NH

OH

H2CO

H2S

NO2

OCN

SiN

C3O

SO2

C-

S-

SiCH3

CH3OH

N+

O-

SiH+

NO+

SiH3+

PH2+

SiH5+

HCl+

PN+

NO2+

CH4N+

CH3CO+

HPN+

HNS+

PC2H3+

CH3

HNO

C2H2

CP

CH2+

CH5+

SiH2+

H3CO+ CH3OH2+

HCP+

CS+

HSO2+

NCO+

PCH3+

HSO+

HOCS+

CO2

OCS

PH

HPO

HCP

CH4+

HCNH+

H2CO+

S+

PH3+

H2S+

H2Cl+

HNSi+

CO2+

SO2+

PCH2+

PNH2+

H3SiO+

H2PO+

H3C3O+

HSiO2+

CH

NH2

HCO

HS

N2O

C2H

CH2PH

ClO

SiCH2

H2SiO

CHOOH

C+

CH3+

C2H3+

P+

HS+

Cl+

SiCH3+

SiNH2+

H2NO+

PCH4+

PNH3+

CCl+ CHOOH2+

H2CCl+

OCS+

CH2

CH4

CO

NO

O2H

NS

CN

SiH

PN

CCl

H-

SiH4

HNSi

SiO2

CH+

OH-

C2H4+

HNO+

PH+

O2H+

H3S+

SiCH2+

SiCH4+

NS+

PC2H2+

C2H3

SiH2

C3H

HCS

PH2

C5N CH3OCH3

C2S

SiC3H

C4S

CN-

C3H2+

HCSi+

CP+

H5C2O+

C3N+

SiC2H+

SiC2H3+

S2H+

SiC3H2+

CNC+

C2HO+

H2SiO+

C2H7O+

C2N2+

C3H2O+

HSiS+

SiC3+

HC3S+

SiC4H+

HC4S+

HCN

H2O2

SiH3

C3H2

C3

C4H

SiNC

SiC3

SiC4

HNC

CH3CHO

HC3N

C2H6CO

CH3CN

C2H2+

SiH4+

C3+

C3H3+

C3H5+

C2H5O+

C4H2+

C4H5+

PC2H+

C5H4+

HC2S+ CH2NH2+

CCNH+

H3CHO+

2H5OH+

H3CS+

H2C3N+

CCP+

H2S2+

SiC4+

C4P+

H2CN

C3H3

C5H

CCN

C3N

CCP

C3P

C4P

CH2NH

CH2CN

H2CS

SiC2H

SiS

H2S2

CH2CO

C2+

HCN+

H2C3H+

CH3CN+

HC3N+

SiNC+

C2S+

SiC3H+

C2H7+

C2O+

CH2CO+

C2H6O+

C3O+ C3H6OH+

H3S2+

PC4H+

C2

S2

C2H4

H2C3

C4H2

SiC

CCO

HCCP

C2H6

H3C3N HCOOCH3

C3S

C2H+

H2NC+

C2H5+

C3H+

SiC+

SiN+

HCO2+

C4+

C4H3+

SiC2H2+

C5H2+

CH2CN+

H4C2N+

HC3O+

PC2H4+

H5C2O2+

PC3H+

C3H4

C2H5

HCSi

SiC2

C5

C2H5OH

SiC2H2

HS2

CN+

C2H6+

CCN+

C3H4+

C4H+

SiC2+

SiNCH+

SiS+

CH3OH+

HC2O+

HNCO+

H2CS+

C2H6OH+

ClO+

H4C3N+

OOCH4+

S2+

C3S+

C4S+

C5H4

C4

C5+

C5H3+

C6H3+

C7H2+

C5N+

C6H2

H3C4N

H3C6N

C5H+

HC5N+

C7H3+

C8H+

C2H6CO+

C7H2

C7N

HC7N

C4N+

C6+

C6H5+

C7H4+

C8H2+

H2C5N+

C7H4

C6

C7

H2C4N+

H3C4N+

C6H+

C7+

C7H5+

HC7N+

C6H4+

PC4H2+

H2C7N+

C5H2

C6H

C7H

HC5N

HC4N+

C5H5+

H4C4N+

C6H2+

C7H+

H4C6N+

H3C5N+

C8

C9N

HC9N

C8+

C9H+

C9H5+

C8H

SiO

C9H2+

C7N+

C8H4+

C10+

C9H3+

C9N+

C8H5+

H2C9N+

C9

C9H2

C8H3+

C9H4+

H3C9N+

C8H2

C9H

H3C8N

C9+

H4C8N+

HC9N+

H3C7N+



Ris. 1. Raspredelenie obilii HCN v modelyah


Ris. 2. Raspredelenie obilii HC3N v modelyah


Ris. 3. Raspredelenie obilii HC5N v modelyah

Chernoi strelkoi na risunkah ukazano obilie himicheskogo soedineniya, poluchaemoe pri ispol'zovanii neizmenennoi bazy UMIST 95.

Vidno, chto velichina razbrosa obilii cianopoliinov vozrastaet s uvelicheniem kolichestva atomov v molekule. Dlya HCN velichina razbrosa na polovine vysoty gistogrammy ravna 1.00 poryadka, dlya HC3N 1.50 poryadka, a dlya HC5N uzhe 2.05 poryadka. Ochevidno, eto svyazano s uvelicheniem dliny cepochki himicheskih reakcii, privodyashih k obrazovaniyu cianopoliinov s uvelicheniem chisla atomov v nih.

V nastoyashee vremya ryad specialistov rassmatrivaet vozmozhnost' ispol'zovaniya otnosheniya obilii nekotoryh molekul dlya ocenki vozrasta molekulyarnyh oblakov. V chastnosti, dlya etih celei predlagaetsya ispol'zovat' otnoshenie obilii cianopoliinov (naprimer, HCN/HC3N, HC3N/HC5N) [6]. V svyazi s etim interes predstavlyaet razbros znachenii etih otnoshenii v rasschitannyh modelyah, predstavlennyi na risunkah 4 i 5.

V oboih sluchayah velichina razbrosa otnosheniya v poschitannyh modelyah sostavlyaet priblizitel'no 1 poryadok, chto sushestvenno huzhe tochnosti nablyudatel'nogo opredeleniya otnoshenii HCN/HC3N i HC3N/HC5N. Takaya nizkaya tochnost' model'nogo rascheta etih otnoshenii privedet k pogreshnosti togo zhe poryadka pri opredelenii vozrasta ob'ektov pri ih pomoshi.

Privedennye vyshe primer, na nash vzglyad, horosho illyustriruet sushestvennost' vliyaniya oshibok opredeleniya konstant skorostei himicheskih reakcii na fizicheskie parametry modelei molekulyarnyh oblakov, a, znachit, na interpretaciyu nablyudatel'nyh dannyh po takim modelyam.


Ris. 4. Logarifm otnosheniya obilii HCN / HC3N

Ris. 5. Logarifm otnosheniya obilii HCN / HC5N

4.3. Inye raspredeleniya oshibok konstant himicheskih reakcii

Vse ocenki v etoi rabote sdelany v predpolozhenii ravnomernogo raspredeleniya oshibok konstant skorostei himicheskih reakcii vnutri ukazannogo v UMIST 95 diapazona. Na nash vzglyad, predstavlyaet interes, kak izmenyatsya privedennye v rabote rezul'taty v sluchae inogo raspredeleniya oshibok konstant himicheskih reakcii. V svyazi s bol'shimi zatratami mashinnogo vremeni (na raschet 10000 modelei Pentium 4 2,4 GHz 512 Mb memory tratit bolee 70 chasov) nami ne byl proveden podrobnyi analiz etogo voprosa.

Odnako nekotorye ocenki vse zhe byli polucheny. Dlya etogo byl proveden raschet 5000 modelei himicheskoi evolyucii sredy s privedennymi v tablicah 1 i 2 fizicheskimi i himicheskimi parametrami, no s ispol'zovaniem inache izmenennyh failov UMIST 95.


Ris. 6. Raspredelenie obilii HCN v modelyah pri umen'shennom razbrose konstant skorostei himicheskih reakcii

Vse koefficienty sluchainym obrazom ravnomerno var'irovalis' v predelah diapazona 12,5 %. Poluchennye pri etom gistogrammy dlya HCN, a takzhe dlya otnoshenii HCN/HC3N i HCN/HC5N privedeny na risunkah 6, 7 i 8.

Risunki 6,7 i 8 namerenno sdelany v tom zhe masshtabe po osi X, chto i risunok 1, 4 i 5. Vidno, chto harakternyi vid gistogrammy sohranilsya, odnako shirina sushestvenno umen'shilas', chto i sledovalo ozhidat' pri umen'shenii razbrosa znachenii konstant himicheskih reakcii.

Podobnym zhe obrazom vedut sebya raspredeleniya oshibok otnoshenii obilii. Sootvetstvuyushie gistogrammy predstavleny na risunkah 7 i 8.


Ris. 7. Logarifm otnosheniya obilii HCN / HC3N
pri umen'shennoi razbrose konstant skorostei himicheskih reakcii


Ris. 8. Logarifm otnosheniya obilii HC3N / HC5N
pri umen'shennoi razbrose konstant skorostei himicheskih reakcii

Shirina razbrosa otnoshenii umen'shilas' proporcional'no velichine razbrosa konstant himicheskih reakcii. Raspredelenie zhe v celom sohranilo harakternyi vid. Takim obrazom, est' osnovaniya polagat', chto izmenenie raspredeleniya oshibok ne izmenit kardinal'no vyvody, sdelannye v dannoi rabote. V to zhe vremya, osnovanii polagat', chto oshibki opredeleniya konstant himicheskih reakcii men'she, chem ukazano v opisanii UMIST 95, net. Sledovatel'no, dannye, privedennye v punkte 4.3 sleduet rassmatrivat' tol'ko kak teoreticheskuyu ocenku haraktera povedeniya razbrosa obilii i ih otnoshenii pri izmenenii harakteristik razbrosa konstant himicheskih reakcii.


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